First, score it well with a wallpaper scoring tool. Then mix 1 cup of liquid fabric softener in a gallon of warm water and wipe it on liberally with a soft t-shirt. Let sit 10 minutes. Then peel off.
In the past, I have used hot tap water with vinegar. Place drop cloths on the floor and with a towel or sponge, soak the wall from ceiling to floor. Then, using a putty knife, gently push up against the wall paper to scrape it off. It's messy yes, but; it will also take off the old glue from your walls.
here is how I removed wallpaper - https://www.charlestoncrafted.com/2017/01/24/experience-removing-wallpaper/
I use a 50/50 mix of vinegar and hot water in a spray bottle. Saturate the wallpaper and let it sit for a while to work. Use a putty knife and scrape off. Also use the same mixture to wash off any glue residue with a sponge.
Bathroom wall paper removal.
I turned the shower on for 30 min on hot water and start scraping of where wall paper was peeling of. I took as much as I could and stopped. Turned the shower on back for 30 min and turned it off. Let it set for 10 min and scraped the remainder of wall paper. Wiped it off with dry rag to remove the glue. Nice and clean in two hours.