Roll your wallpaper strip loosely with the paste side out and print side in.
Place the rolled-up wallpaper in the water tray, and submerge it according to your paper's instructions. (Some paper may require only a few minutes, while other paper may need more than 15 minutes.)
Remove the paper from the water after the allotted time by pulling it up carefully from the outer edges. The roll will begin to become unfurled; let the excess water drip off back into the tray. If you notice any dry spots, lightly dab them with water using a sponge.
Place the paper down on your hard working surface print side down, paste side up. Carefully pull one end up toward the middle, nearly folding it in half but not making a crease. Do the same to the other end of the paper. This process is called booking and allows the paste to penetrate the paper and let the paper "relax" so it is easier to hang. The booking time will also vary by the paper you have, so be sure to check the instructions.
Unfold the paper, and carefully grab one end by the corners. Climb your ladder and hang the first piece, starting at the top and pressing your way downward. Use a brush to push out any air bubbles in the paper.