Instructions
Click on the padlock image next to your gold action bar at the bottom of the screen. This will unlock the buttons on the action bar, allowing you to place new macro hot keys on the bar.
Drag and drop the buttons you want to make macros of from your silver action bar and place them onto your gold action bar. These can be special abilities, attacks using different types of ammunition or items such as shields and repair bots.
Lock the gold action bar buttons in place by clicking on the padlock image a second time. Your macro hot keys will now be usable and correspond to the number keys on your keyboard. For example, the first macro hot key on the left of the bar will be linked to the "1" key, the second button will be for the "2" key and so on.