How do you use the force in jedi knight jedi academy

In the Single Player mode, force powers are progressively added on through the campaign, and some powers you can even chose the order in which you learn them by applying a "force point" to a given power to increase its level before the start of a mission.
In Multiplayer mode, force powers are located under the player menu, where the available "force points" for that server can be allocated to whatever powers you wish. However, some powers may be disabled on some servers.

In order to use these powers once they have been applied, you will need to respawn by bringing up the console (press shift + ~) and typing "/kill" without quotes and pressing "enter". Your powers will be activated by their assigned F keys or Function keys by default, but can be reassigned to different keys via the Controls menu.