As we mentioned earlier you can recruit units and also use them to gather or steal resources. But in order to get to those resources some times you will meet opposition from the other side and the conflict will result in combat.
There are different types of units that can be stronger or weaker against other types, so pay attention to which units you chose to send out on the world. The different types have also different statistics that can define a better use for them. For example the Armored units can carry a lot of resources and take a ton of punishment thanks to their thick armor, but they are not a good offensive unit due to their lower attack. Picking a good combination against your opponent can be the difference between victory or a shameful defeat.
Once a combat has ended, some units may end up being wounded. In this case Commander, you can recover them from the Civil District. Recovering units is cheaper and quicker than rebuilding them from scratch.