You start the game by selecting your race, your region and your professions, after what you'll get in your town where you take quests from the adviser and he will introduce you to the game basics. You'll see that the game si not just like in AoE:O by having the town as an avatar, no her in DoF the town is the heart of the game. It lives even when you are offline (don't forget that while offline you can not be attacked) produces materials, golds builds up and whatever missions you gave to your workers to do, they'll do it with a slight speed penalty.
You not only build up your town and look at it how beautiful is, but you have to defend it from other players and you can , beside upgrades, produce the military units you need to battle with them. As i sad, the resources to buy all those are coming from peasants that works while you play or offline, quests, pvp or even when you just simply zoom in to the map of your army's position and kill every npc on that zoomed in place in a real time strategy game style. Think of it most like Total War but way more advanced...