What Jim said.

Socializing the afternoon before and the evening after is optional.

Actual day at the track:

Facility opens 7-ish
Mandatory Driver's meeting 8:30am
First run group [advanced] on track at 9:00am...
...parallel with a short newbie / refresher classroom session also at 9:00am
Last session ends somewhere about 4:00 or 5:00pm (or earlier, if you or your car are done)

In addition to the event fee [if you're running a car], there is a small ($10 or maybe $20) facilities fee for anyone coming onto the grounds, even for spectators and crew.