For those saying you have to use a script for this, shut it. I myself have made a working two player system using both the ASDW keys and regular arrow keys. It's fairly simple to do, with conditional branches and checking if the X, Y, Z, or R button is being pressed (which are A, S, D, and W respectively on the keyboard). Just play around with that for a little bit and it should work for you. If not, I can post my system directly for you, though I'd rather you try to make it yourself and learn on your own.