Local Multiplayer Help?

Hi, me and my team have been developing this game for a while, things are going smoothly, but I think we may need some help. We have been trying to figure out how to get local multiplayer, on ONE screen to work. Like a platformer type of way? Any video tutorials, or step by step, pictures etc…

BONUS: On the Side Scroller when we added the other character he seems to be off of the plane, like he seems to be about 2-3 spaces back according to the imaginery line that the player 1 will walk along. How can we make him on the right plane/line?