Start an Attack
From Desert Operations Wiki
To start a battle, you must look for an opponent. If you have already assigned your Fleet positions, you can sent an attack direct form the island view by clicking on the base and can also be done by clicking on the Gun symbol. Then in the fleet view you must click "OK". On the right in the info box under "Action" you will see when the attack will arrive at the opponent location.
An attack is sent directly from the military-menu in the command center.