Building your own keyboard is supposed to be fun. You do some research to figure out what you want. Maybe order some sample switches to try out, pick out a keycap set you like, and eventually settle on a kit.

When you order your kit it’ll include a case, a top plate, and a circuit board. If you get one with hot swap sockets you will not have to solder anything. You can literally just press the switches in.

Then when you’re done you screw everything together, put your keycaps on, and you have a working keyboard. Sometimes you have to flash the firmware as a final step but that’s not rocket science. You do not have to know how to program.