What do you need to know? Wallpapering isn't hard, but if it's your first time it helps to have two of you, one to paste and one to hang the paper.
You need: plumbline, wallpaper scissors, papering table (unless it's the kind where you paste the wall, even then it might help for measuring), ladder, paste brush and bucket (any bucket), paste, long ruler (easier than tape measure), pencil, paperhanging brush and cloths. Actually, our long ruler has a spirit level on it which is easier than plumbline. A wallpaper trimmer is not essential but makes cutting the ends easier.
Take your time, measure everything twice, especially if the paper has a match in it, and cut the paper a little longer than you need then trim once it's on the wall. Plan out where to start and finish (I think you're supposed to work away from windows so that the light doesn't highlight joins), and if you have a big pattern and/or chimney breasts etc. work out where the paper will need to go to look best.
When you're cutting the paper, mark the top and bottom as you cut so you don't get confused. Cut a couple of pieces in advance so you can plan the matching edges on the board rather than on the wall.
For a good finish, turn off the electricity and unscrew fittings such as wall lights or light switches, and tuck the paper behind them.
I'm sure there must be lots of youtube videos if you're thinking of giving it a go.