Moving an object with the arrow keys

I'm working on a project which i want to emulate a mario game (side-scrolling rpg). I wan the user to be able to control the character with the forward, back and up keys but so far I've had no luck with the "let arrow keys control" and the "when 'X' key is pressed" methods. any help is greatly appreciated.

If you want it so that while you hold right key, the mario moves to the right, left left, jump up, then for left and right, click the events menu, click on when <key> is pressed, and then right click on that event and select change to while <key> is held. Select left key. Then, add in the during part, mario or whatever move left or whichever way it is facing that moves it left in the world. Same for right. For jump, just do when <up key> is pressed, mario move up five meters or so. For gravity, search for thread "Video Game Concepts vol. 2 - Gravity" in the Share Worlds section of Sharing and Collaboration. That should help explain the concept of moving down until you hit the ground better than I can.