How to apply self adhesive wallpaper without messing it up?

This link has lots of hints:

https://livetteswallpaper.com/blogs/wallpaper-101/removable-wallpaper-dos-and-donts-how-to-install-self-adhesive-wallpaper

This may help: https://www.justmeasuringup.com/diy-wallpaper/

Very slowly peel the backing and apply at an angle. I use a damp cloth to run out the bubbles as I go. Also a good plastic squeegee will help to ease the bubbles out. Don’t move forward until you have worked out all bubbles and creases. About an inch at a time.

Here a good link for you:

https://abeautifulmess.com/5-creative-ways-to-use-peel-and-stick-wallpaper/

How to Install Self-Adhesive Wallpaper in a Snap!

https://tidywithstyle.com/self-adhesive-wallpaper/

I start at the top and I don't remove all the backing until I am rolling it out on the wall. I go slowly and use a credit card or other stiff tool to remove bubbles as I go.

I also do exactly as Homeroad does and it works very well. Main thing to remember is to not rush but to take your time in affixing the paper and then pulling a little bit of the backing material away at a time.

We just did this in our pantry! Here's the entire DIY, but the short of it is, measure well, go slow and make sure your walls are really clean and smooth. https://www.exquisitelyunremarkable.com/2021/06/how-to-put-up-peel-and-stick-wallpaper.html

Line it up using Plumb guide lines. Unroll without stretching a bit at a time. Use a flat edged smoother to remove bubbles as you go.

Measure the wall so you have a streight line to follow from ceiling to floor follow that line

heres a vid to help you out, a extra set of hands wouldnt hurt either

This stuff is tricky for sure, likes to stick to itself and tears very easily so really, the best tip I have is to go slow. Only remove as much backing as you need at a time.

apply in stages ..remove backing as you are ready to attach to wall