How does Attacking work?
Once you've built a few units and want to attack an opponent, just go to the map and click on the village that you want to attack. There you select "send troops". It's important that you don't forget that every village has a base defense and that the opponent might have units as well. All units have different properties, which makes some units better for attacking and others better for defending. You can find details about the units' skills in the Unit overview.