Exactly as the title said. I have no idea on how to defeat the first 2 as I've always gotten close to beating them but lose when they have roughly 500 health left And I also don't know where to find the third.

dont know if you still need help help in the first one, I had rita use crush, thorn protect on first turn, and used the attdwn skill on main gal

and then just used basic atks in between cooldowns

slightly late, but walk behind the windmill