I always wondered how to get an ISBN for a self-published book. Now I know. https://www.myidentifiers.com/identify-protect-your-book/isbn/buy-isbn

Also, here is a link to self-publishing on Amazon:  https://kdp.amazon.com/en_US/l/print-on-demand

I found these on this here blog: https://notjohnkdp.blogspot.com/