Where are the three stages? How does the concert viewing work? Two of them are in Tomorrowland, while the main stage is set up in front of Cinderella Castle. If you didn't review the schedule online, you can get a printed copy at the part to help you decide where you want to be and when.
Because the three stages are fairly close together, you don't have to rush from one end of the park to the other to catch the acts in different areas. Tomorrowland is a hub just off Main Street, so you bear right to get there or keep going straight ahead to get to the castle.
Check out the list accompanying this article to see what each of the stages looks like and to get a little more information about each one.