Someone recently posted their website, I think, on another thread. But for a simple explanation, hotels pay a fee to have it instead of having their own shuttles. Then, for a very small price, it's just like having a hotel shuttle for unlimited back and forth. Instead of being for just one hotel, it will make stops at a couple of hotels, but we've never had one that took us more than 3 stops and 10 minutes on the trip. You purchase your tickets through your hotel front desk(it's only for hotel guests--it's not an actual 'Anaheim' transportation system for anyone) and wait at a bus stop in front of your hotel. There's a sign there so you know where to be and the bus will see you. Just show a pass to get on, and it takes you to a drop off area right next to the plaza where you enter the parks and Downtown Disney.
When you want to return to your hotel, you go back to the drop off zone, you find your shuttle's color/letter sign, like blue D and wait for it to come. You show your pass again, they pick you up and take you back to your hotel. They run every 20 minutes to half-hour, I think. The last shuttles of the day at closing are packed and you might not get a seat, but they'll squeeze you on and it sure beats walking or getting a taxi! We have had great experiences with them. The drivers we have had are courteous and helpful, and it's so nice to get dropped off right out front of your hotel at the end of the day. Does that answer your question?