[Nonfractal]

Mr flip did a quick youtube in pairing  controller to a chip

https://m.youtube.com/watch?v=L17pFvcMC6A

From  memory:
Take car off track
Power up scp
Hold down the down-arrow lane change button AND the round brake button with your thumb.
Rotate the curvemax to select the channel you want
With you little finger depress the throttle trigger, the 7 segment channel display spins
Drop the car on the track
Release the throttle

The car should now be controlled by the scp.

Be aware that the slot it system does not truly "pair" a car to a controller. It just sets both to the same channel.

To set  second car to be controller to the same scp, repeat the above using the same "channel" number.
Ensure that other cars are powered off while you perform pairing.

Alan