How to make your keyboard PCB
Here is a good tutorial about keyboard PCB making: https://github.com/ruiqimao/keyboard-pcb-guideAnother, more general: https://kbwiki.ai03.me/books/pcb-design
And a series about designing the FHAN pad with KiCAD: https://www.youtube.com/channel/UCg98oJZNffR9nDLJNkorjqw
Finally, a comparison of prices of different manufacturers: https://pcbshopper.com/
Add compatible screw holes for popular cases.