ISBNs - KDP

Hey guys 🥰

I am thinking about publishing exclusively on Amazon but I’m a little confused about the free ISBN. Do I get one free one for paperback? And another for hardcover? Or just one free one for the book?

if I can get two isbns for paperback and hardcover, then how do I link them or put them together into one page? (So people are clicking my book and the two formats come up). I’d love a tutorial video if anyone has one!

Thank you!