There is a GDI Construction Yard in this area and it must be destroyed before attempting to destroy any other buildings as they would simply be rebuilt by GDI as long as the Conyard is alive. So this is the mission's initial primary objective. Note that the CY is protected by base gates requiring a Green Key Card.
Once the Conyard is down the next target becomes the GDI Power Plant providing power to the Advanced Guard Tower. Players will require a Yellow Key Card to access the PP and destroy it. Optional targets are the GDI Weapons Factory and GDI Tiberium Refinery. Destroying them is advisable because without a WF the GDI can no longer produce vehicles and with the GDI Refinery down the unit production will be halved.
More screenshots and intel will be available later :)