In the past whenever I needed a directory added to a disk I just booted up the utilities and created one. I knew there was a way to do it under ProDos, but never bothered to look it up.
While I was setting up the disk image for Basic Games I needed s couple of subdirectories. I figured it was time to look it up, so out comes my copy of The New Apple II User’s Guide. Two minutes later I had my answer. CREATE. I created my two subdirectories, loaded and saved animal into the correct directory and uploaded the disk image, so I could link to it on this page.

If you don’t mind me asking, how did you look it up in the book? The index, an appendix, or did you go skim through the chapter?
I just flipped the book open to look for the list of commands in the appendix and stumbled across it in chapter 7 on page 223.