FPV Drone Racing has many different types. There is indoor aka Tiny Whoop racing which uses quads that are under 50 grams, are no bigger than 50mm props, they have ducts, and are almost always run at 1s indoors. Then there is the larger class which takes pretty much any drone over 100 grams, you don't need ducts (and would preferably not have them period for performance reasons), props must be between 2 inches and 6 inches, and you can do 2s and higher (you usually want 6s for performance reasons). So you will need the following for this tutorial.

Supplies

A complete fully functional racing drone.
A transmitter for the racing drone.
A flight sim.
A adapter for the transmitter for use with flight sim.
FPV monitor or goggles.
Batteries.
Lots and lots of props.

Step 1: What Drone Do I Want?

You want something you feel comfortable flying. If you have never flown a quad copter before or are a noob get a tiny whoop. They are super small, you won't hurt anyone with them (if you do you'd have to work at it), and can be flown indoors safely without breaking anything unless your aren't careful.

If you feel really comfortable flying a tiny whoop or have flown larger quads before you can either build your own quad copter which is a lot of work and a lot of sourcing of parts, or you can buy one prebuilt. Normally anything bigger than 3 inches prop wise you can buy pre built drones for and I would recommend that for anything smaller than or equal to 3 inches when it comes to props. Why I might be saying that? Three inch quads or smaller have really tight soldering jobs. They are not for the feint of heart. It's so much better buying one so you don't have to worry about breaking it.

Building one is a lot of fun and if you don't know anything about building quads and don't want to fly a tiny whoop this is what I would recommend and the reason being is stuff out of your control does happen and if your quad breaks your going to want to know how to fix it. Here is what you will need from a diy quad build.

Frame.
Quad motors for the frame.
VTX
Camera
HD Camera like gopro (optional)
Flight controller for the frame
Satellite receiver or whatever receiver that is compatible with your FC and remote.
Props for the motors.
Compatible batteries.
Battery connector
Battery strap or holder

Recommended prebuilt quads

E013
Mobula 7
Mobula 6
Eachine Trashcan
Some tyro models
Diatone Rabbit models

Step 2: Choosing Your Remote

Frsky is pretty much what everyone uses. It is a open source transmitter that can be pretty cheap and is the second cheapest remote off of this list. It can be pretty long range depending on what remote you choose and they have a wide range of remotes.
Spektrum is a great beginners radio but that is it. If you want anything better I would recommend parting with spektrum. It is super expensive as well.
Flysky is a great radio and is super cheap. The build quality is a bit questionable but works okay for what you pay for. Not only that I use these radios and all of mine are super long range and are not expensive at all. You will look super weird for flying one of these for you will probably be the only one flying one of these during a race but they are not at all for beginners. Not at all intuitive these remotes are.

I would recommend one of these kinds of remotes depending on your preferences. Good luck!

Step 3: Flight Sim

You will want a flight sim for many reasons. Quads are expensive and break easily and if you don't have a space to fly this is the way to go. Quad sims are cheap too. Velocidrone is my go to simulator. It has a wide variety of drones in it versus DRL from steam and from what I paid for is very cheap. It was around $30. DRL is more for people hoping to enter the drone racing league for being good at that sim is a requirement for it. There is only one kind of drone in that sim which is why I don't really recommend it often.

Step 4: Viewing Your Footage

You will want fpv goggles or a fpv monitor for viewing your flight footage. Goggles are like virtual reality except it is for seeing the footage from your drone while flying. Every vtx on a drone has a wide variety of channels you can listen to. These channels are not encrypted meaning anyone can view them with FPV equipment so don't do anything sneaky for it's not like you would get away with it! FPV monitors are for people like me who either have motion sickness or don't like things being put up to there face. You preferably want something with a DVR. The reason being if you want to record your footage and show it off online or to your friends you want a DVR.

Step 5: Batteries!

Batteries you want lots of for the amount you can safely charge but you don't want too high of a voltage, and you don't want it to be too heavy either. Heavier the battery the less thrust you will have and the more difficult your drone will be too fly. Too high of a voltage can lead to you breaking your components on your quad.

S stands for how many cells your lipo has. 3s stands for three cells while 6s stands for 6 cells. You never want your batteries to completely discharge for that will kill your batteries and potentially cause a fire. You never want to have a 1s battery low on voltage for more than an hour. Every minute that battery is low on power kills the battery. 1 cell is approximately 3.7 volts.

You want a charger for the kind of battery you are using. This will vary upon battery to battery.You also want a connector on your battery that is rated for what you are trying to do and is compatible with your drone.

Step 6: Props!

Props are normally measured in inches. But tiny whoop props are measured in MM. Usually a prop will be in the format of **x**x* like for eample 30x52x3 props. You maybe wondering what do those numbers mean? 30 is short for 3 inches, the prop's diameter. 52 is the angle in inches the prop is. Greater the number the greater angle of attack the prop is. This can generate more thrust larger the number depending on what your motors are rated for. The last number is how many blades you got. You generally don't want something more than 3 blades on a propeller for a quad copter

Step 7: Software

You will have to configure your drone after you bind it with your remote. Binding your quad will vary upon remote to remote to receiver to receiver. Binding basically connects your remote to the quad so you can control it. Beta flight is the go to software for configuring drones. It is a lot to configure correctly. I highly suggest reading through the betaflight documentation. It would be a whole tutorial in it's self.

Step 8: Knowing Your Quad

There are four motor on a quad. Each is spinning a propeller proportional to the motor diagonal from it as shown in the diagram. The reason for this is if there weren't an equal amount of propellers spinning in two different directions the quad would rotate really fast in one direction uncontrollably. This is similar to why a helicopter needs two blades minimum to fly.

Not only that in the flight controller there is an IMU. An IMU senses direction and rotation similar to a gaming nun-chuck. It is essentially a combination of a Gyroscope and Accelerometer. This is used to control the quad.

Every remote has two flight modes. I personally only know how to fly mode 2 which mode 2 is pretty standardized. Left stick forward and backwards is throttle while left and right is yaw left and right. Right stick controls pitch with forwards and backwards and right and left controls roll.

Step 9: Flight Modes

Acro: Acro is the standard flight mode for almost everything. Yaw and throttle are controlled as they would in stable mode but roll and pitch is slightly different. If you pitch or roll the quad doesn't roll back to self level like it would in stable mode. It will keep going that direction unless you pitch or roll to compensate for it.

Stable: Don't fly stable ever. It is a bad habit to get into. It teaches things that are not necessarily a good thing. Stable is a mode that after centering the sticks your quad will self level. If you pitch forward and then release your quad will go forward and then self level.

Horizon: Horizon does everything stable mode does except you can do loops. Pitching and rolling too far on your remote can cause you to do a loop in mid air.

Step 10: Safety and Regulations!

Never fly over or near people. Never fly anything but a tiny whoop indoors. Always remove your props when your battery is plugged in indoors. Never fly over 400 feet.

Anything over 250 grams in the USA and in most countries is deemed illegal if you cannot get a aviation license for it. In the USA you can fly a drone without complying with the law for our laws on model aviation aren't really enforced at all but if caught you will be charged. You are not allowed to fly anything in the USA with any kind of signals over 800mw. This includes radio and VTX signals. I understand the greater the signal the better it will fly but those laws are there for a reason. They can cause interference. But although I wouldn't recommend this FCC laws are not enforced at all in the USA. I have known people for years who have always violated those laws and have not once got caught. Do it at your own risks.

Step 11: Conclusion!

My first drone was a RXD-250 quadcopter. A local dealer scammed it to me with a really fancy remote and I had never flown anything like it. I can't believe they recommended a 5 inch quad to someone who had never flown anything like it before.

A few years later I got the e013 from eachine. That was my goto quadcopter for the next year. After that is was the qx65. It was a step up from the e013 but not by much. Then I got into brushless by flying mobula 7's. They were a lot of fun but aren't my favorite kind of quadcopter any more. I don't like tinywhoops any more. They break too easily and aren't anywhere near as fun as some of the larger stuff.

Now my goto quad is the Diatone gt r349. Great quad and is a lot of fun. I have crashed it so many times without any scratches on it what so ever.

If you have any questions feel free to ask. I would be happy to answer them. Thanks!