Anyone experienced in Warcraft 3 editor: How do I ign unit positions/starting points?

I need to create a 2-player non melee map with starting locations for red and blue, and give player 1 a few starting units, including at least one hero. I've selected and dragged the individual units together (from units palette) to form 2 groups, but can't figure out how to actually ign starting points. It says they're player 1 and player 2, but when I test the game, I materialize as a peasant unit randomly generated on the map. Any help much appreciated.