Measure your wall and determine how much product you will need in square feet, plus a little extra. Make sure your base floor trim is installed and all your edges are level and square. If your wall or floor is uneven, your shiplap may need extra adjustment to appear straight.
To further customize your shiplap, you can cut custom boards from plywood to fit your square footage. If you choose this option, ensure your total square footage is divided evenly to the width of each board. Use all necessary personal protective equipment when sawing, and cut your boards lengthwise. Sand your boards smooth after cutting, and paint as desired.