What does it mean to wake up at 7 am?

It doesn't mean anything. I'm not sure what kind of answer you're expecting here. Waking up at 7 AM means that you were asleep for some undetermined amount of time, and then something caused you to wake from sleep at 7 hours after midnight.

There is no more meaning to the act of waking up at 7 AM than the literal meaning of the Words. It's like asking, "What does it mean to sit down on the toilet?" or "What does it mean to light a match?" or "What does it mean to wipe your nose?"