The tile comes in sheets with a backing that you just peel off. The adhesive is very strong. All you do is peel off the backing and press it on to the wall.
What I wish I had known…
I wish I had kicked off this project by painting the wall black. I went back with a tile grout because between the sheets of tiles, you could see the white wall. If I had painted that wall behind the tile black first, I doubt I would have had to use grout at all. This would be my #1 advice to anyone who does this project!
My second #1 advice is make sure you’re using a level. Walls aren’t always straight so use a level as you go to make sure you’re on the right track. Don’t trust the wall because chances are it’s not actually straight.