Start here for Philidor and Lucena, then work through Vancura and test yourself with the exercises.
Rook Endgames: Essential Positions
3 studies · Curated by Bosburp
I've picked three studies to help you work on rook endings. Start with the basics, try the positions yourself, and save rook and bishop versus rook for when you want a tougher challenge.
The last study includes a bishop as well as rooks, so I'd treat it as a step beyond the basic rook endings.
Original studies belong to their credited creators and open on Lichess.
A suggested study order
Another rook-endgame study I'd recommend alongside the first one.
For a tougher challenge, try rook and bishop versus rook. Study the winning techniques, but pay just as much attention to the defensive resources.