You need some experience in CS2D entity placing. Read this carefully. This tutorial only shows the way to make the door, not other thing.
- Make a walls with 2-tile hole. 2. Place func dynwall at the space. Name the both "d1". 3. Place trigger use in the front of the two sides (both). Set the trigger "d1". DONE!
How to use
Press (default) E in at the front of the door.