pizzaman- click the arrange button and then there should be a screen with a bunch of units on it. the empty circles on the left are your battle units and spells. click on units and spells and click again on the empty circles to select those units and spells for battle
hate it when you're trying to keep the big one on the screen, and then your turrets accidentally get the powerup, and you can't shoot without shooting the big one off the screen, and your turrets just shoot it off.
for 25 lives left, you can get 0 deaths on everything except on 1-3, 1-4, 2-2, 3-3, 5-2 (I know with a lot of effort, you can also get 0 deaths on 2-2 and 5-2, but it's simpler the first way)
For all of you people saying that the march and retreat buttons do nothing, you have to click on the picture of the unit on the bottom of the screen, them tell that particular unit to march forward or go back