Pooping and peeing are basic human functions. These are simple in a sticks and bricks house with indoor plumbing but take planning in a camper.
The simplest approach is to stay near places where toilet facilities are available. This might be in paid campsites, a friend's driveway, 24hr stores, fast food joints, rest areas, etc. Apps like Where is Public Toilet may help locate them.
Read more info on toilets.