You will need to have a good saw to cut the pieces to fit around existing fixtures in the bathroom.
Hi Jami. I'm Cindy. Measure the wall first. Then cut the wood pieces to fit using a circular saw. You may need a jigsaw for special cuts like notches, corner cuts, etc. Decide if you want to paint or stain the boards. Then use a nail gum to install the boards. Stagger the seams. Once you have your boards installed, fill the nail holes with wood putty. Allow to dry overnight. Then sand the excess off. Good luck Jami.
Here’s how we did it very cheaply: https://www.frugalfamilytimes.com/2018/05/how-to-make-vertical-shiplap-paneling.html?m=1
You can get underlayment sheets cut into strips at the hardware store. Then attach it with a nail gun, cutting the pieces where necessary.