If you mean how to use adult Pampers as in adult diapers you simply lay down and then place the back of the adult diaper with the tapes underneath your butt.
Then pull the diaper up between your legs.
Next take one side at a time and tape the tapes to the side and ensuring a snug fit.
If you mean how to wear Pampers as an adult then you would have to modify those pampers such as by taking the landing strip off and cutting it in half and then glue one of the cut in half landing strips to each side of the diaper.
Then wrap some packing tape around the diaper to keep it from falling down.
When someone is wearing diapers it can be hard to tell if they are wearing diapers.
However if the person wearing a diaper is wearing a thick enough diaper or the diaper is wet and sagging in their pants or shorts you can usually see the outline of a diaper bulge in the back of their pants.
Sometimes you may also see a diaper bulge in the front of their pants or shorts as well.
Another way to tell if someone is wearing a diaper is to look for the diaper waistband that may peek above the shorts or pants when the person shirt rides up.
Even when I wear diapers in public I can hardly tell that I'm wearing them even when I look in a mirror and nobody has said anything to me or gave me any looks.
So it can be really hard to tell or know if someone is wearing a diaper.
And even though we know most toddlers wear diapers it can also be hard to tell if the toddler is wearing a diaper.
I once was at the park one day and I saw a 3 year old boy who was wearing shorts and his shirt and I could not tell that he was wearing a diaper until he got off the swing and started climbing up to the slide.
Then his shirt rode up and I could see a Pampers Cruisers Diaper sticking above his waistband.
Before that I was not aware that he was wearing diapers.
However there have been times I've seen 2 year olds and 3 year olds who had a diaper bulge in their pants or shorts when the diaper was wet and sagging so that is one way to tell.