First of all, you have to load the doormanager resource on your server.
Create a door In-game
Get a door you want to see open. In this case, it's the ammunation. Open your chat, type /getdoor and hit enter. A mouse cursor appears. Now find a spot on the door until it gets a bit transparency like in this picture:
Just click the door and you get a new chat message it should look like this "Your door ID is X"
How to open the door?
You need the command /setdoorstate [ID] [LOCKED] [HEADING] in this case, it would be door ID 6.
So open the chat again, type /setdoorstate 6 false 1 and hit enter.
Now you should be able to open the door. Just run against it.
Create a door with code
Instead of loading doormanager resource through server settings, put this in your meta.xml
<include resource="doormanager" />
You first need to register the door, then Change the door state
int i = API.exported.doormanager.registerDoor(int model, Vector3 pos);
API.exported.doormanager.setDoorState(i, bool locked,int Heading);