Follow these steps for dipping and folding pre-pasted wallpaper:

  1. Fill water tray* with lukewarm water and set it on the floor at the end of your table.
         
  2. Completely immerse the rolled strip (pattern side in) in water and slowly pull it out, pattern side down, unrolling as you pull, laying it on the table.
          
  3. Once you've pulled the entire piece out of the water, look for dry spots. If you find any, sprinkle a little water on them with your sponge and work the water in lightly with your fingers.
       
  4. Fold the top of the strip back to the middle of the strip and the bottom back to the middle, being careful not to crease. Allow 10 minutes in this folded position for wallpaper to "cure."  

* An alternative to the water tray method is to use an "adhesive activator" for pre-pasted wallpaper, which is available in your local Sherwin-Williams store. It's applied like paste and eliminates the need for soaking each strip in water.