This is the most basic model of SqUke. It sounds a little tinny and is not overly loud, but it does play and is relatively easy to make. The body is completely plywood with toothpicks frets and machine screws/nuts for tuners. The strings are mono-filament fishing line. Look in the "Discussions" for more information.
I've created an Instructable, rather than repeat what is already published, I'll provide a link:
https://www.instructables.com/id/SqUkulele-Make-Plywood-Ukulele-From-Hardware-Store/
https://www.instructables.com/id/SqUkulele-Make-Plywood-Ukulele-From-Hardware-Store/