But you, the leader of your Covenant, will grow only by duking it out with the hordes of monsters outside the gates of the shared Covenants' territory. By completing prescribed quests and by bashing the life out of every monster you see, you gain experience, money, and indirectly gain power and influence. Your avatar can equip a whole mess of gear, use and learn many different active and passive skills, and do all the sorts of things you'd expect in a top-down Action/RPG/RTS hybrid.
Sounds like standard dungeon-crawling fare, right? Well, yes. But you're on a time limit. Efficiency and strategy are key, because the AI-controlled Covenants are working ceaselessly to do the same thing you are. Slack off, play too inefficiently, or play in an unbalanced manner, and you're likely to get wiped out. Getting "wiped out," by the way, is done only by destroying a crystal in your little hut of a home base. This is your "respawn" point, of course.
Good news, though! Whether you "win" or "lose," the game allows your character to undergo an infinite loop of "new game plus," with some penalties. So if you weren't ready for the world you'd created the first time around, just keep going! However, all quests are reset, so if you were enjoying the series of quests assigned by the NPCs in town, you'll be starting over on them.