Steaming has always worked well for me. See if these help.
Water!. Protect your floor with painters plastic sheets. Then a sponge soaked in water to soak the wallpaper. Wet it enough and the wall paper will release in huge strips, Give the water time to soak through. If you start on one corner, just keep wetting the entire wall until you don't see any dry spots. Then use a spatula to slide under the paper to start then you can pull huge strips off. When you are finished, just roll the plastic sheet up with all the paper inside. Let the clean wall dry 24 hours or more before doing anything else. Give the water time to soak through. This can actually be fun. Your arms, shoulders and back may be sore a day or so, but that is great exercise also. Then toss your tennis shoes in the washing machine with towels to get the glue off of them. Have fun. Grandma
See above regarding protecting your floor. I mix about a tablespoon of fabric softener in a spray bottle with warm water. Use a scoring tool to scrape up the wallpaper, then spray liberally. Let it sit for about 20 minutes. The wallpaper usually comes off fairly easily. If not, repeat.
It’s a lot of hard work, but it is doable. You need warm water, a scoring tool, a scraping tool, floor coverings, arm strength and perseverance! Score the top couple of wall paper layer; using a cloth or thick sponge, wett a section of the wall liberally with warm water—then start scraping off the wall paper. The nice thing about plaster walls is that this won’t damage them.
Good luck. Kathy P