Just completed this…
It’s quite easy. Read on.
The design was drawn on the computer and printed on overhead transparencies (see next photo)
Cutting the stencil. This is a laborious process so do take your time. I cut this in a few sittings, getting up in between to do something else. That works for me because when I get tired, I make mistakes.
Stencilling onto the book cover. I used white acrylics paint. Again, slow is good, and keep lifting the stencil to see if you have got enough paint on the design. I used the (almost) dry brush method (as the name suggests, no water and very little paint each time I dabbed my brush onto the surface), but a foam roller will also work well.
I made another 2 bits of stencil for the cup cakes above. All done!