When you start the game you generally have one or two full squads at your command. The sergeant is usually in front followed by the other marines, one of them been the flamer marine.
The main game screen shows your current view. In the upper left corner is the name of the active marine. Below this it shows the amount of ammunition left, valid only for flamer marines. In the upper right corner are the number of action points (AP) and command points (CP) left. The lower left corner shows a mini-map of the immediate area and in the lower right corner the menu appears.
The movement keys (up, down, left and right) are used to move the target ring around. The target ring will appear red whenever the active marine has a line of sight to the position under the ring.
The fire button is used to perform movement. When pressed the marine will attempt to move one action closer to the target ring location if a path can be found. The marine will first turn around if he is facing the wrong direction. The marine will also open doors and attempt close combat with genestealers in his path. Selecting an immediately adjacent square can be used for finer control such as moving backwards.
Game button A and B are used to change to the next or previous marine respectively. While game button D is used to center the target ring on the active marine.
Game button C is used to fire the marines weapon. The marine will need a line of sight to the target. The storm bolter can be used on genestealers and doors while the flamer can only be used on genestealers. Game button C is also used to open and close doors although they must be directly in front of you for this to work.
The left soft key is used to toggle the mini-map to fullscreen view while the right soft key is used to toggle the menu.
The menu is used to end the marines turn when you have finished your turn. The genesteaslers will then take their turn. You can also pickup, drop or take an object when appropriate. You can use the overwatch mode and clear your storm bolter weapon of a jam. You can change the games settings or quit back to the main menu.