Some pictures of the Studio 2 Towers I'm building, which include pictures of the bracing, are at the link. The braces are identical in size to the tops and bottoms of the cabinets, so I cut them all at the same time. I then drill four holes in the corners of each brace and cut out the interior with a jigsaw. The resulting "frame" slides right in. The gluing gets a little sloppy, but it doesn't matter.

There are of course many other ways to do it. Each person develops and uses his own preferred techniques.

• Studio 2 Tower Pix