There are two ways - well, I’m sure there are lots more but two basic ways I know so far of making a hardcover book. One is gluing the covers to the text block endpapers and then gluing the spine covering, the other is the casebound method of creating the cover separately and gluing that to the text block endpapers. I need to try the other method to see if I like it. I chose the casebound method first as it’s the one sturdy hardback books are made with.
As to cover material, you can use paper, fabric, leather or book cloth, which you can easily make yourself. I made my own floral bookcloth for my watercolor journal.
I enjoyed watching and learning some techniques Sea Lemon - YouTube but she is a bit self-taught and there are some details she glosses over (like cutting the corners on the cover material) or that she learns later. I can send you links to the pro video channels as well. But Sea Lemon is a good intro. She even has a video on how to make your own bookcloth.
Yes, I might be a wee bit bookbinding obsessed 
