Moving a MC by pressing letters on the keyboard, need HELP! Example inside

Hello all,

Well I posted this question before , but never got an answer that I understood or could get to work - so now that I have something to show I thought I would post it with the question again.

Have a look at this :

Now, once the screen says “GO!” I want player 1 to be able to move that blue horse across the screen to the finish line (where it will have a hitTest to decide the winner).

Right now I have no idea how to do it. Can someone please help me out?