You are free to read or watch TV until your normal bedtime. Then the lights are turned out and it is time for you to try to fall asleep. A low-light video camera allows a technologist to see you from a nearby room. They will have to enter your room if a sensor comes loose. They will also have to detach the wires if you need to go to the bathroom during the night.
Nearly everyone falls asleep during the study. Most people do not sleep as well as they do at home. This will not affect the results. In most cases, you do not need to sleep for a full eight hours to find the source of your problem.