Double check the car before you roll out to the site. Make sure your fluids are all good to do. Double check your battery to make sure it's secured. Go through the car and remove any loose items. Maybe air the rear tires up a few psi more than the fronts (might help with understeer).

Get there early and walk the course. Mention this being your first time to someone at sign up and ask if there's anyone there who might be willing to walk the course with you or mentor you during the day.

When you actually race, be smooth. Chances are, you won't need to get out of 2nd gear, so keep both hands on the wheel unless you're actually shifting gears. You're going to be into 2nd quick and then probably stay there for the rest of the course. It all depends.

Above all else, don't be a choad and have fun. Get pictures and share the results with the group.