Win condition: Rout the enemy
This is essentially a tutorial map.
Mycen, the Gold Knight, is your powerhouse unit. He instructs the child units Alm, Gray, Tobin, and others to safety, and can do most of the heavy lifting himself. If you want, you can put the kids to work, as they won't die too easily and can take a few hits from Slade's weak forces, but be careful.
Use the kids to snipe off weakened foes if you like, or simply leave most of the work to Mycen. Defeat all enemy forces to complete the map.