The Beginners' Room can be found under Rooms> Roomlist> Lessons. This room is helpful to beginner's in both getting a rank and teaching games or reviews.
The KGS Teaching Ladder can be found under Rooms> Roomlist> Lessons. This room is helpful to beginners and more advanced players in finding teaching games and reviews. No ranked games or private games are allowed in this room.
The Computer Go room can be found under Rooms> Roomlist> Social. This room contains many bots that are useful in getting a rank or just playing for fun.