Once you have enough levy you can start thinking of Army Recruitment.
Depending on the resources available in the settlement they can train to become infantry, scouts, archers or heavy cavalry.
When you have raised an army, you can go about using it.
Troops are user to conquer territories for your kingdom.
You can also move troops around, putting them in territories (as long as you are the garrison commander of the territory) and taking them out to use in your army. You can also send troops to other players, all moves except attacks cost resources. The amount it will cost is determined by the number of territories you are the garrison commander of among other factors. And as you get territory further into the game, militia options will become available.
Infantry are the general foot soldiers of the army.
They are the cheapest to recruit, but also the least effective unless fielded in large numbers.
To recruit infantry you will need the following resources: 5 food, 10 silver, 4 iron and 1 sword(s).
The eyes and ears of your army, they can give you an advantage in battle.
To recruit scouts you will need the following resources: 10 food, 50 silver, 2 iron and 1 horse(s).
Relatively cheap troops, but still quite effective, they can pack quite a punch if things go well for them.
To recruit archers you will need the following resources: 5 food, 25 silver, 1 wood, 2 iron and 1 bow(s).
The most powerful, and the most expensive, they can crush larger armies in one go but can be cut to pieces if not well supported.
To recruit heavy cavalry you will need the following resources: 10 food, 250 silver, 1 wood, 15 iron, 1 horse(s), 1 bow(s) and 1 sword(s).