1. Depends on the race but usually you find the registration table, get your bib and maybe some other goodies. Pin the bib to the FRONT of your shirt. Get there earlier than you think you have to.
2. Eat something light and digestible 2-3 hours before the race. Not a lot of time to experiment and usually the first rule is nothing new on race day. Have you ever eaten before working out? Toast with PB?
3)Depends on the race, that info should be available at the race website, or ask when picking up the bib.
4)There will be portapotties at the start there may be some on the course, again that info depends on the race.
5)Race starts at 9. Do your warmup (personally I would walk 5 and then jog a bit but it depends on how stressed you are about finishing the distance) so that you finish by 8:45. Immediately get in the portapotty line one last time. IF the race is really crowded and the lines are long, warmup earlier
6) I'll attach another link, but basically dont start in the front if you are slow. Try to appropriately stage yourself. If you do have to switch from a run to a walk dont just stop suddenly, make sure there isnt someone right behind you. Dont hold hands or walk 3 abreast in front of runners
7) Someone will stop and help you. Runners are good people. The race will have medical support.
8) it is extremely unlikely to happen. But look at the map ahead of time and have a general idea. But yes the courses are generally marked or have volunteers at the intersections.
Here is a link to a fairly comprehensive list, some serious, some funny, but overall quite helpful. It was originally written for a 10K, but still has good help
HAVE FUN!!!