I decided to copy a design of a book cover by František Cubr. Here is some more information about the book. I copied an older copy of the book that I found on pinterest.
It was difficult to reproduce the same color effect. I learned not only about blending but also rasterizing and merging layers.
I'm not 100% happy with the result. It's hard to get an identical color effect. I would like to see the yellow making green and red lighter, instead of darker. I think I may redo it and just copy the colors from the original instead of using the blending option.