disclaimer: don't blame me for not showing step by step this is just supposed to be a reference and I'm just saying what i done and the result ,it has some core flaws like noise so don't do exactly like I done and expect an outstanding result, and finally forgive me for grammar errors because I just don't care if I'm not misunderstood than its fine, now to the interesting part.
Step 1: Make the Structure of the Steering Whell
first of all you gotta make an mount point for your steering wheel(that disk thingy over there) i recommend you using a cupsaw but if you dont have one large enough to fixate your wheel on (i made mine with lots of time a circular saw and some sandpaper) ,next up you gotta have an axle anything you can bolt your mount point on and it wont rotate apart from the axle should do the trick(in my case i used a broom stick)i recommend strongly that you use ball bearings cause they reduce noise and friction but its up to you, at this point you should already drill the holes do fixate the mount point to the axle.
Step 2: Make a Base
now you just have to make a base for your steering part, its totally personal and the only thing its gotta have is a way to fixate that axle+mount point on (i used metal straps to fixate the bearings) and avoid using nails because you will probably have to disassemble it to fixate the potentiometer
Step 3: Fixate the Potentiometer
now what you gotta do is to strap a pot on the axle its desirable to avoid belts and pulleys as they tend to cause delay (in my version the pot is directly connected to the axle using a small metal plate to fit the gap on the pot) other way to do it is to use cogs but beware of straight and centered holes or you just use a resin 3D printer in the ideal world.
Step 4: Make a Rotation Limiter
this can be one of the hardest parts depending on how you done the base, keep in mind that its utterly necessary as a way to protect the pot (i used a couple of bolts and a nail stuck in place with masking tape), just remember to place it somewhere its not gonna interfere with springs, elastics or stepper engines used to return the steering wheel to the center or force feedback.
Step 5: Make a Base to the Pedals
for a vertical pedal setup like mine you gonna need a base an strong bar or tube (mine is an printer part) and structures to keep it on the desired height
Step 6: The Pedal Time
you will need 3 pedals(throttle, brakes and clutch) they can be whatever scrap you have, they just have to be strong enough to withstand your "kicks" (i used aluminium square tubes) if you don't have a way to drill straight its better to use square tubing with some method of noise mitigating (metal with metal friction)(i used a felt strap between the two metals).
Step 7: Making the Pot Feels Your Foot
now you need to make the pedals rotate the pot when you step on then, for it i used a servo like scheme on the pot, a rod to pull it and a mount point for the pivot on the pedals
Step 8: Still Making the Pedals Feel You
you should end with something like it after you're done, try to figure it out, and try not follow it blindly and end with lots of metal battering noise like i did
Step 9: Now the Pedals Have to Go Back
that should be obvious enough but the pedals should be in idle position when you're not stepping on it, you just need to put an spring or rubber in a way that in makes the pedals return and have some feedback.
Step 10: Finalle
now all you have to do is to wire it up, i used an arduino leonardo with the joystick library 2.0 ,any microcontroler or old analog joystick should work ,anyway here's the coding i did (it include 4 axis and 11 buttons)