Dumping the holding tanks of your RV is an essential thing when you're out on the road or in a campground.
I learned how to do it 26 years ago when I had my first motorhome. Prior to that, I had a tent trailer that didn't have holding tanks. What you'll need to dump your tanks is a sewer hose and sewer connector (see above photo).
Emptying your holding tanks is not at all difficult. About Travel has an article on "How To Dump RV Tanks".
They begin it with:
One of the common misconceptions about owning a RV is that dumping the holding tanks is a dirty job. Truth be told, it is, but not in the way you think. Dumping the holding tanks is an essential part of RVing. When you know how to do it right, it’s not a dirty job, but if you make a mistake, well, that’s where the dirtiness comes into play. We’ll show you the basics of dumping your holding tanks so you can avoid the mess.If you are new to RVing, you should read the article.
To read further, go here.