I didn't buy it =( It's leftover from a project at my parent's house, they were going to throw it away but I took it with the hopes of salvaging it.

I like the old-fashioned glue and nail approach recommended by others, any reason you would recommend a trowelable substrate? Like one used for a backsplash I assume?

Thank you! I wasn't sure if they would just rip the paper off the drywall or not.

Liquid Nails with a brad nail or two seem to be the popular approach.

Nah she just loves butt stuff