Upgrading the Palace will increase its defense against attack. Upgrading the Palace Lv.will allow you to upgrade your Workshop and Temple Lv. The Workshop and Temple Lv. cannot exceed that of the Palace and you must upgrade both before you upgrade the Palace again. Pressing will also select the next most damaged unit if the currently selected unit does not need repairing. Click on the Workshop to build new units, buildings, walls, and land. Upgrading your Workshop will increase its defense and unlock new, more powerful weapons. If it gets destroyed you'll lose the ability to build new units until you rebuild it.