qmk new-keyboard

Then answer the simple questions and qmk will generate an info.json config, keymap etc.

Then you will need to edit you info.json under the matrix pins columns and rows to match which GP pins you used on your mcu.

Edit key map, etc.

qmk compile -kb “name of your keyboard” -km default

…or whatever you named your keymap if you changed it from default.

Compiling will generate a uf2 file that you copy to your mcu after you put it in boot loader mode. You will need to copy it to both halves.

Done.