Applying the Wallpaper Installation Process Mark the wall with a level laser or level ruler. Start from the top and ensure the first strip is perfectly vertical with the marked line. Smooth out bubbles and wrinkles with a brush or roller. Align subsequent strips carefully to maintain pattern continuity. Trim excess wallpaper at the top, bottom, and corners with a sharp knife. Wipe excess glue with wet sponge of clean water. View Section 4 View Section 6