Leanpub author Davide Barranca has generously written a post about using Leanpub to write a book, and then make a print version of the it, using the print-on-demand service Lulu:
https://www.davidebarranca.com/2019/04/printing-leanpub-books-on-lulu
Many thanks to Davide for creating this helpful and detailed resource!