Step 1: Safety Procedures
The first part of learning to fly should be safety. Since you will be working with a flying machine, it can get quite dangerous. Make sure that if you have a copter larger than a dinner plate, tie it down to the ground or surround it by a cage so you do not injure those near you or yourself. Also, if you think you are going to crash, turn the throttle all the way down to 0 so that you don't break the quad or break what it will run into depending on how powerful of a machine you have.
Make sure not to get fingers close to the blades. If you have a powerful machine, serious injury could occur.
Always unplug the quad before trying to fix anything on the copter. One flip of the switch while working on it could result in serious injury.
Step 2: Terminology
Yaw its the direction the quad is facing. When you start flying for the first time, make sure to face the quad with the front end away from you. This will make it easier to fly because it's right will be your right, and its left will be your left. When you turn it so that it is facing you, these controls are now backwards.
Pitch is the rotation for moving the front and tail end. This means it moves the front end higher than the tail end, or vise versa. This aspect controls whether the quad is moving forward or backward.
Roll is the rotation from side to side. As you can expect, this makes it move to the right or to the left.
Altitude is the height at which the quad is flying. Keeping the quad at a lower altitude while learning to fly is an easy way to get used to the controls.
Above is a helpful picture featuring a plane that explains pitch, roll, and yaw if the text is confusing.
Step 3: The Controller
The left most stick controls the altitude and the yaw. The default area for this to be in is down (a motor speed of 0) and in the middle. It should automatically want to be in the middle for the side to side aspect. The side to side area of the controller is the yaw.
The right most stick controlled the pitch and the roll. The pitch is in the up and down direction and the roll is the side to side motions.
The little switches can control the default setting for how the quad wants to fly. A simple controller may not have these, but if the quad doesn't take off in only altitude, changing these will help that process.
Step 4: Starting Flight
When you start flying for the first time, as I have said in other parts, you want to maintain a lower altitude. So slowly lift the altitude node to test how quickly the quad will take off with the motor settings.
Do not try to move it. Just start with trying to maintain a constant low altitude, and slowly rising it to higher altitudes.
Step 5: Movement of Quad
Do not work with the yaw, keep it facing away from you.
Now try using the pitch and roll to make it go in a circle in the clockwise direction. Once you have the hang of that, do the counter-clockwise direction. Learning to change between these two will come after mastering both directions.
Step 6: Reverse Direction
Continue with this direction as you did in the first direction. Once you get good at it facing you, it is time to work on a more advanced way, the figure 8.
Step 7: The Figure 8
You need it to face the direction you are going to start. First, make it do a figure 8 while facing away from you. Once you can do that, turn the yaw so it faces you and try doing a figure 8 in that direction.
Once you master both of those, you want to make the quad always face the way it is going in the figure 8. This is where you will have to pay attention to the yaw, pitch, roll, and altitude.
Once you accomplish this, you are now a master of flight!