Download or clone the whole firmware and navigate to the keyboards/retro_refit folder. Once your dev env is setup, you'll be able to type `make` to generate your .hex - you can then use the Teensy Loader to program your .hex file.
Depending on which keymap you would like to use, you will have to compile slightly differently.
### Default
To build with the default keymap, simply run `make`.
### Other Keymaps
Several version of keymap are available in advance but you are recommended to define your favorite layout yourself. To define your own keymap create file named `<name>.c` and see keymap document (you can find in top README.md) and existent keymap files.
To build the firmware binary hex file with a keymap just do `make` with `KEYMAP` option like:
```
$ make KEYMAP=[default|jack|<name>]
```
Keymaps follow the format **__\<name\>.c__** and are stored in the `keymaps` folder.
