1) Get a tool from Zinsser called the "Paper Tiger". It's a palm-sized round tool that pierces many small holes through the paper. This enables the actual stripper solution (like Dif) to reach the glue layer. You have to keep the area damp for a few applications of the stripper. TIME is your friend here...follow the instructions on your stripper.
2) The paper should come off pretty easy IF there was SIZING put on the wall b4 the paper went on!! If there was NO sizing applied...good luck...it's gonna be a long afternoon! You may have to tear it off using a rented wallpaper-steamer.
3) After everything is rinsed off WELL...let wall(s) dry, and put on a coat of STAIN-BLOCKING primer. Give a slight nod to an oil-based primer.
4) NOW you're finally ready to apply TWO coats of paint. Use top-quality rollers & Brushes. This isn't the stuff to skimp on!!
>>> Hope this all helps!
Faron