Just use the left and right arrow keys, it was only a test, not a game. (You can't jump, I don't know how to do that :I)
Finally, after about 10 tests, one of them finally works! This is only a test, I didn't work super hard on graphics or anything, I just quickly made a stickman and placed a platformer script (made by me) from my backpack to the script area, and started testing with the ScrollX variable. (I obviously added in the yay and yippee after I succeeded :P) Yes, there are glitches and bugs, but this is my first success, give me a chance :P