First of all I commend you for the willingness to learn and try to do jobs that you are unfamiliar with and likely have not done before on any size vehicle.
It's not rocket science and you can do it. It does take some upper body strength and some dexterity plus a willingness to get unbelievably dirty.
Go to a store close to you and buy a cheap mechanics "creeper". This will make it easier to roll around under the coach particularly if you are parked on a hard surface. Then roll around under there with a good flashlight and look things over. Use some throw away gloves like you use at the dump so you can touch everything. Take a roll of shop towels too.
If after looking the situation over your decide you don't want to tackle it yourself first, I suggest you take a road trip to the closest Speedco. They are the quick lube place for over the road trucks. They are reasonably priced and they will allow you to go down in the pit and watch while the work is done. Let them use their filters and then you will have a set for on the road, which is always a good. Idea.
Then gather the knowledge you gained, make sure you have proper tools and next time try it yourself.
You can do this if your really serious about it. I've done mine for years. And I'm an old guy
Be sure to post and let us know how you do.