It's very simple.
Split the field diagonally, the lead has his half, the trail(Center for 3) has his half. But on the three man, the trail has to first check out the sub box and offsides, then move to help on the crease and off ball play.
Anyways here is a site with diagrams to help you understand what I am saying.
http://www.zlax.net The link is on the left side for one/two/three man mechanics.
