Hang wallpaper horizontally by using heavy-duty wallpaper paste, foam paint roller, seam roller, sponges, utility knife, measuring tape, scissors and wide metal putty knife, advises HGTV. Have another person help you hang the wallpaper properly.
The first step is measuring the length of the required strip, explains HGTV. Apply the paper around an inner corner by placing measuring tape in the corner and overlapping around the next corner by one inch. Smear some paste to the back of the wallpaper after cutting it to length.
Make sure to avoid putting excessive paste on the front of the paper. With the assistance of another person, start putting the paper evenly in the corner. Line up the paper with the edge of the piece beneath it. Instead of using plastic wallpaper smoother, use your hands to smooth out the piece. Use a seam roller to ensure that the edge sticks around the corner. After wiping off excess glue, repeat these steps for the next piece.
Cut the top strip in the same length as the previous strip, and trim one inch from the width to make the paper flush with the ceiling, notes HGTV. After pasting and hanging the paper, place a putty knife near the bottom edge of the crown molding, and use a utility knife to cut the paper.