I use Loc Tite Quick Grip and only have to add a very few panel nails at the seams.
I start near the middle of the wall, making sure the seams will fall in the middle of the studs.
Never have the panels sitting on the floor, it's not going to be level, leave it about 1/2" up off the floor. The base boards will cover the gaps.
That first panel has to be dead plumb.
You start in the middle of the wall so the cuts on the ends will come out about equal.
The end cut will need to be scribed in for a nice tight fit. I will cut then a tiny bit longer then it needs to be and sand it to fit where it meets the wall.
If it's done right there's no need for ugly inside corner moulding.
When the panels hit the wall and I have it sitting plumb I go over the wall with a hand floor roller to smooth out the glue.
Lowes sells a nice chair rail that acts as a panel cap moulding because it already has a dado cut into the bottom of it.
If this is a bathroom I would not suggest using the prefinished MDF wainscott, I've seen it fail to often.
Use real wood and sand, prime and paint or stain and seal instead.