F8 (combat window)
Choose a fire control under "selected fire control".
Assign missile launchers to the fire control under "assign weapons to selected fire control" by selecting them and clicking "assign".
Choose a target under "assign contact as a target" by selecting one and clicking "assign".
Your selected fire control now has missile launchers assigned to it, as well as a target.
Click "open fire" on the right of the screen.
Watch the fear in the eyes of your ennemy
So, rule of thumb : you choose targets for a fire control, not for weapons. You need to assign weapons to a fire control before firing.
