What are Doors?
Doors are simply put, movers that are activated with a Trigger to move out of your way.
- 1 x Static Mesh (to use as the doors shape)
- 1 x Trigger (KFuse or KFProxy is fine)
 How do I create a Door?
 Step 1
First, go to the static meshes browser and choose a static mesh for your door. You can also custom make one using brushes and saving it by right clicking on the group of objects going to make up the door, choosing convert -> to static mesh, save in the package "myLevel" (exactly written like that) and whatever group and title you want.
Once you have a mesh selected (not put into the map, just highlighted in the browser) right click on that mover icon . Then click on KFDoorMover. The static mesh you chose will now pop up as a purple colored wireframe in your viewports, in the middle of the red brush. You now have a door mover.
 Step 2
The first order of business is to put the door where it will be located when it is closed. Then, right click on the door and you will see the option "mover" (it's the second one down). Click on keyframe 1. Now move the door to the position it will be in when it is open. This could be a rotation or shift in axis location or both. Right click on the door mover -> keyframe 0 (base). This puts it back where it should be so the door doesn't show up as open in your level.
 Step 3
Second order of business is to alter the door's tag. Trigger events control what doors open by matching the tag of the door to the event of the Trigger. If you have a trigger with an event named "door1" and a door somewhere on your map has the tag "door1", then when a player presses their "use" key in close proximity to that trigger, the door with the same tag as the event trigger will open/close (Move).
So, right click on the door, click properties, drop down the events tab, and change the door's tag to something appropriate like "MainHallwayEntrance"
 Step 4
Now put in a trigger. Go to actors -> triggers -> UseTrigger -> KFUseTrigger and put it somewhere on the map (highlighting a surface in the perspective viewport, right clicking and choosing "place KFUseTrigger" is usually the easiest way to place the trigger where you want it). Right click on the Trigger, go to properties -> events -> event = "MainHallwayEntrance". Now that the trigger event name matches the door tag name, this trigger will open the door when a player uses it. So, place the trigger in the middle of the door.
And that's a wrap.
Keep in mind though that if any doors share the same tag, they will ALL open/close by using that one trigger (likewise you can have multiple triggers open/close the same singular door). Hence, you can get double doors or "buttons" on faraway walls that "unlock" and open a door.
Now that you know all this, the Mapping Guide will make much more sense and tell you how to make a double-hinged swinging door.
 Where is the Mover Icon?
Right click on that and you'll see some options come up, a few of which are Mover and KFDoorMover.