Scrape the walls with a drywall knife or sand them with 50-grit sandpaper to remove smaller imperfections and fill any holes with a nonshrinking joint compound so you don’t have to wait until it dries and apply another layer. Remove all light switch and outlet faceplates, heat registers and light fixtures. Never hang wallpaper over unfinished drywall.
Before hanging the wallpaper, you can choose to add a coat of wallpaper primer (also called sizing), which is an acrylic-based liquid that helps make your paper stick more easily and also makes the removal process go more smoothly. I don’t do this for my peel and stick wallpapers, this step is optional.
Cut and size the wallpaper. Always check the length and width of a wallpaper before you order it. When measuring a room, you need to keep in mind the pattern of the paper. Sometimes the pattern on one panel needs to line up horizontally with the pattern on the panel next to it.