1. get one of those wallpaper scuffer things. They can now be found with three heads on them.
2. bucket of water
3. a tile sponge with abrasiveness on one side.
4. putty knife or two
5. garbage can - with liner
6. spray bottle for water
7. spray bottle for wallpaper remover stuff
I first quickly peal off as much of the paper that will come off. Each is different, but some come off really easily. Others not so much.
Then I use the scuffer tools. Apply water next and let it get soggy. Peal off as much as you can.
Work in small areas you can keep you with or it will just dry up and you have to rewet and work it again.
For stubborn areas use the wallpaper remover stuff spray. It is stronger in smell than water and does tend to dry faster.
Good Luck and have lots of fun.