Starting a single player game

I'd like to create a button on the menu that simply starts a mission called start.mis. i thought i might be able to do this using Canvas.setContent(start.mis);, but that doesn't seem to work. as you can tell, i have NO clue what i'm doing :) the art tools included with the engine rock, though :) haven't had any problems creating terrain, painting it, dropping in bsps. all of that stuff works great!