Secure loose seams with wallpaper paste so they lie flat. Remove any residue, dirt or grime from the wallpaper. Even out wallpaper seams by applying drywall mud to the seams, allowing to dry and sanding smooth. Remove any dust from sanding with a damp cloth and allow the surface to dry completely.
With your brush, paint (cut in) around the perimeter of the wallpapered surface. Start at a top corner and continue along the ceiling and around the baseboards.
From the bucket, pour paint into a tray and work your roller into the tray until it is fully loaded with paint. For best results, use a 3/8" - 1/2" roller cover.
Starting in a 3' x 3' section at the top corner of the project area, roll the paint onto the wallpaper in a "W" formation.
Work the roller back and forth across the section until the "W" is completely filled in. Be sure to roll over the cut in area as well.
Forming a column from ceiling to floor, paint the next 3' x 3' section directly below the previous one.
Repeat the process of forming columns and blending sections until the project is complete.