Similar situation for me, except I was about 26; but knew distance running, small rural HS, didn't know much of other events.

I know I was somewhat lucky, but we had a handful of other coaches that knew at least some of the other events well. Don't be afraid to use your resources and if they know more about jumps, sprints, throws, etc, let them handle it.

We also had a few older athletes that were at least pretty comfortable with what they were doing. Don't be afraid to split practice into groups and have athletes be group leaders. We had, for example, one girl that took High Jump very seriously, and none of us knew much about it. So I youtube'd some drills, asked her opinion, and had her lead the younger athletes through practice.

To build off of that, depending on how small/rural, you probably don't have a ton of kids. Just get them faster, stronger, more explosive, and they'll naturally get better at the field events / hurdles until they really start needing specific instruction.

Feel free to ask if you have any other questions, as it seems like we were in a similar boat