You can faux do it by drawing lines with pencil & smearing or sharpie. You can cut plywood and put up. Use flooring. Pine 1 x boards are what shiplap was originally made with.
Here are some ideas and tutorials for you to consider. I hope this helps!
You can get underlayment plywood cut into strips at the hardware store or you can use tongue and groove boards. Attach them with a nail gun.
Here's how to install it: https://thehoneycombhome.com/how-to-install-shiplap/ and here is how to get the look without power tools: https://thehoneycombhome.com/shiplap-accent-wall-the-easy-way/