There are sort of two resorts in one there.
The Contemporary resort has rooms in the tower building, and the garden wing. In the CR you'll find hotel rooms, not villas, club level is offered, and there are also suites, which also come with club level privileges. The restaurants, lounges, and shops are located in the tower building, along with the monorail station. The Contemporary tower is the big A-frame building that the monorail goes through.
A few years ago, they added the Bay Lake Tower, next door to the Contemporary. This is a
DVC resort, and is the big round tower. BLT offers studios, 1-bedroom, 2-bedroom and Grand Villas (3-bedrooms). There are only villas in this building, no non-DVC hotel rooms. It's connected by a bridge to the CR tower, and guests at BLT use the restaurants, shops and monorail station in the CR tower.
Both resorts share the monorail, buses, and boats, and recreational facilities. The pool at BLT is for use by BLT guests only (it's gated), and guests of both resorts may use the CR pool.
Hope that helps!