How to start a game:
When your team is ready press the start button in your barracks. Once both teams have press both buttons the game will start and the barrack doors will open.

How to pick a team:
When you join a siege game you will find yourself in a room with teleporter(s). In h2siege map there are three teleporters. The one with the picture of the ballista is the defender's teleporter. The one with the catapult is the attacker's teleporter.  If you using the center teleporter it will randomly assign a team for you.

How to change teams:
The only way to change your team is to reconnect to the server and go into the other team's teleporter.

How to change classes:
To change classes press "=" or "-" key. It will then display the next class. You will become the next class after you die. Note: When random is selected, your class will be assigned randomly every time you respawn. When you first join a game your class is set to random.
You can also change your class by typing "prev_class" or "next_class" in the console.

How to open doors:
Some doors are open by using the ACTION key or ATTACK key when your standing in front of the door.
Note: Some doors can only be opened by a certain team.
Note: You can't open a door, that is triggered by ACTION key, if your holding the ATTACK key down.

How to use elevators:
Elevators work the same way the doors do. When you are standing on the elevator hit the ACTION key.
Note: Like doors, some elevators can only be used by a certain team.

How to use ballistas:
The use a ballista, simply stand next to the ballista you wish to use. Then you should get a message that says your in control. Once you see the message you should notice that the ballista faces where ever your crosshairs points. To fire the ballista use the ACTION key. Tip: First aim the ballista and then hold the TAB key to move your camera without altering your aim. This way you can see how close your aim is to the target. It is also easier to aim the ballista in first person mode. Press the "F" key to go into the first person mode and press the "R" to go back into the third person mode.
Note: In h2siege map the ballista doors are opened by pressing ATTACK key (Shooting the ballista will not open them).

How to use catapults:
To turn a catapult one must stand at the center of the catapult. Once there you should get a message saying your in control. Now face the front of the catapult and slowly turn to the side you wish turn to. Note: If you turn too fast the catapult will not turn with you.
You can fire the catapult two ways. The first is by using the ACTION key when your in control of the catapult or by hitting the catapult with your blade or fist. Warning: Hitting the catapult will damage it.

How to load barrels on the catapult:
To load a barrel you must first get the barrel on to the catapult. You will have to push the barrel close to the catapult and the press the "L" key to lift the barrel onto the catapult. Press "L" repeatedly for better results. Then place the barrel onto the launch pad and fire the catapult. The barrel will automatically go on the catapult if you push it again the catapult, but it will be on the edge of the catapult. You will have to move it from the edge or else the barrel may backfire on you when you launch it.
Note: The farther from the center the barrel is, the higher it will go.