Oh it's a bad job, I took down 4 rooms of it in my 1968 brick ranch including two versions of wallpaper that had the foil inlay and some crazy designs... the other two were country plaid.
Also took out the sculpted shag wall to wall orange carpet over the hardwood floors too- what were they thinking!
First see if you can hand strip the bulk of the paper, peel up some edges and go to it. Even if you only get the top paper layer of the wallpaper off this is a good first step.
If it holds fast you are in for a lot of work (ask me how I know). If it comes off in sheets keep going until you get all you can off by hand and with spackle knives/ scrapers etc. What will be left is wallpaper backer and adhesive.
Get the "Paper Tiger" and wallpaper stripper (I used DIF) from the hardware store, score the wall with the paper tiger. Don't use a heavy hand, you don't want to damage the drywall underneath and have thousands of little holes in it to fill. Mix the stripper with hot water in a paint tray, use a paint roller and extension handle and soak the wall with the stripper solution. Wait a while, soak it again. You can also use a garden sprayer/ sponge but the paint tray trick works great, get a pack of those disposable cheap tray liners as this stuff makes a mess. Cloth dropcloths over plastic dropcloths, newspaper over plastic works too.
Start stripping with different spackle knives/ blades/ 5 in 1 paint tool/ whatever works. If you need to apply more stripper go for it, it's your friend.
Once you get the first round of wallpaper/ backer paper/ adhesive off you may have to go for round two to get off all the extra chunks of paper and adhesive.
Finish with a moist (hot water no stripper) sponge trying to get any additional goo or loose paper off. Rinse often.
When it's all dry sand away, use a sanding block... hopefully you didn't gouge too many holes in the drywall, and the wallpaper didn't pull any drywall paper/ chunks out- that sucks (again ask me how I know).
Spackle/ drywall compound- skim coat where needed, use a flashlight at a severe angle up the wall to see the spots that need it, then after the first coat is dry do the same flashlight trick to see spots that need it again.
Sand... again...
Repeat as needed...
Clean the wall and baseboard and trim, especially above doorframes that harbor all that sanding dust. Swiffer the walls, use a bench broom etc.
Prime, paint. Some folks like to prime the wall after all the paper/ adhesive removal before the first coat of drywall compound goes up then again before the finish paint, not a bad idea.
Prep prep prep... nobody will know the horror you went through when they see that silky smooth top coat of paint- HA!
Oh and wear a dust mask when sanding or you'll have horrible nasal issues, and if the house was built prior to 1978 lead based paint could be an issue. If the drywall was just finished/ spackled, never primed/ painted you shouldn't have to worry about lead based paint.
Good luck!