I just finished a 4-part video series on designing and building a custom 4x4 keyboard - no prior knowledge needed other than basic soldering skills. It goes through the details of designing the PCB in KiCad, getting it fabricated (and even assembled if you like), designing the case parts in OnShape, getting them fabricated or 3D printed, and finally building and flashing the VIAL firmware to run it all. My goal is to make this an approachable project for the adventurous newbie. Enjoy!