Here's another 'how to' I found:
https://www.campingworld.com/blog/rv-basics/how-to-empty-your-rv-holding-tank/Don't let your gray water drain onto the ground.
Don't use excessive amounts of toilet paper.
I'm assuming you don't have big tanks so you're going to have to conserve. Don't let water running when washing hands, teeth brushing, doing dishes. In fact, you don't have to do dishes after every meal. That's wasteful with water. Save you dishpan of water and use it for flushing the toilet. The soapy water will help.. a little to add water to the black tank.
For your first trip you might want to splurge a little and get a full hookup site so you get familiar with your tank capacities and how much you'll need to conserve when you don't have full hookups. It will also give you a chance to use the sewer hose without pressure from other campers parked behind you at the dump station.
Someone said to start off with putting 5 gal. down the black tank. Since you have small tanks a gallon or two would be sufficient.
After you dump the black fill a bucket of water or two (from the outside spigot) and dump them down the toilet and that should clean the bottom residue out good. Then dump your gray tank and the gray water will clean your sewer hose sufficiently. No need to hold it under the faucet to clean it - a very unsanitary practice at a campsite. Your gray will have soap. You're never going to get the sewer hose or tanks completely clean and don't worry about it. Store the sewer hose in it's own plastic tub.
One thing of wanting to bring drinking water from home.... are you ever going to take a long trip? At some point you're going to have to trust your water. We've never had an issue in 16 years of constant travel and getting water from many sources. You can add a water filter to your fresh water system to take out tastes. In fact, it's good to take out sediments (sand) also.
Have fun!
