How to create a 6 x 9 document in Google Docs for self published books

You're a new independent author getting ready to upload your first self published paperback book to CreateSpace or Kindle KDP. Then you see something unexpected. You need to upload a PDF but the recommended size for a novel is 6 x 9, 5.5 x 8.5, 5.25 x 8, 5.06 x 7.81, or 5 x 8. You check out Page Layout in Google Docs. Not only do they not offer these sizes but they don't offer a custom size either. Luckily there is a very easy way to customize sizes using a Google Docs add on. 

See How to Create a 6 x 9 Document for Self-Published Books in Google Docs for instructions on how to do this.