You can practice endings on chess tempo! But you only get 1 a day if you are a free member :( (but unlimited tactics unlike chess.com and harder)
How to best study endgames.

yes, i play on chess Tempo, it's a great site, (I love chess.com, it's just i do use other sites). Lots of tactics and things like that, chess.com would be my first recamendation, chessTempo my second, and chessgames third. I have been looking at suggestions and today i'm going to explore all the book recamendations.
The queen endings are queen vs rook and pawns, and there are plenty of knight endgame principles that are needed other than basic endgame principles.
No they're not. Since you have the book, read starting on page 420. (Hopefully our page numbers are the same.)