Hanging pre-pasted wallpaper is not an easy task. You are supposed to just wet the back and apply to the wall but often the wallpaper needs additional adhesive in order to lay down on the wall correctly. A wheat paste would be the best. Having another person help get it on the wall would be a good idea.
No its not hard to do, have some wallpaper paste on hand. Usually for seams and corners. I fill the bathtub, cut the paper one sheet at a time, let it set in the warm water for a few minutes folded in half long ways and its ready to hang.
Don't rely on the prepasted method - it tends to peel easily. Buy wallpaper paste insted and follow the directions on the can. Make sure your walls are clean and free of grease and dirt. Hanging wallpaper can be done by one person, but it takes patience and practice and you may need help if hanging strips over 8' long.
Very easy to do, is possible for one person to do. Most important thing to remember is to be good at measuring the pieces before putting them up, and then when putting it up be sure to be careful it needs to smooth and have no bubbles, and you can buy a smoothing tool to do this.
Fold the wallpaper on itself then dunk into a shallow flat container half filled with water. Then unrole and place onto wall and squegee as you go. Its very messey.