How do I clip? Yes I've read tutorials and searched here. I do not understand what they say to do. Whenever I try to clip (Trying to make a clip in one of my brushes for a doorway) it either clips the whole brush or half the brush, I can't cut out a square.

I've been working on this for awhile and nothing seems to work.

The short answer is, "yes." You can't cut out a square, you have to make at least four cuts to pull a square out of the middle of a brush.

After you define your clip points, CTRL+ENTER will flip which side of the clip is kept, ENTER will make the cut, and SHIFT+ENTER will make the cut and keep both sides.