Now with the door selected, click the To Entity button. A dialog box should
popup: 
Under Class, choose func_door if it isnt already chosen. Next, set the
angle you want the door to move when it opens with the angle control. You can also choose
up or down with the drop down box. For the important attributes:
- Leave the Name alone, unnamed doors will open automatically as someone
approaches.
- The next four are your standard render options, leave these as is.
- Speed is how fast it will open/close in units per second.
- You can set a move and stop sound from the choices.
- Set how long you want the door to stay open with delay before close, in
seconds. (But 4 seconds [the default] seems to always stay open).
- Next is Lip. This controls how far the door opens. With lip set to 0, the
door will open its entire width (or length) in the selected direction. If it is set
to 4, the door will open 4 pixels less, leaving a 4 pixel lip showing. If you have carved
a track into the wall or ceiling where the door slides to and you want the door to slide
further into the track than the door width so that some of the track will be showing when
the door is fully open, set the lip to -4, and the door will slide 4 units
further into the wall than its width. Basically, the door will slide its width
minus the lip value. If the lip is positive, that means it wont open the whole way,
if it is negative, it will open more than its width.
- Next is Damage inflicted when blocked. This is just how much the player will
get hurt if the door closes on them.
- If you want the door to trigger something when it opens, enter the name of the object to
trigger under target, and set the delay before fire. (It
wont trigger the object until the door is completely open, and the delay will start
after that.)
- Set Fire on Close if you also want to trigger the object when the door fully
closes.
- If you set 'health' to a positive number, you will have to shoot the door and do that
much damage to it for it to open.
- The last important option is minimum light level, which will control how
dark the door will be if no light is falling on it.
Im setting my door to open up, have a delay before close of 3 and a lip of 4 (so
it will open 92).