I need help with the command button.

Everytime i hit the G button nothing happens, Even when i press the G button while facing a soldier.

Nothing pops up, i even tried holding it down.

In case you have no idea what button i'm talking about, it's this one

" Command button:
Use EC options to change it, default is G.
- Double click on a soldier to access the command menu.
- Select a soldier and then a NPC for attack order.
- Select a soldier then a prisoner for execution order.
- Select a Scientist and a locked terminal or container for give a unlock order.
- Double click anywhere to place a marker there.
- Double click on a NPC for air support menu.
- Double click on a prisoner for options menu.
- Select a Scientist or a Wraith then a ordinary object (not NPC) for mine placing order. "

Can i get some help on how to open it up or use it?

Anyone?