1. Fork the github repository: github repo walkie talkie
2. Review the circuit diagram and photos.
3. Add or modify CAD files in the repository
4. Wire one black-style or grey-style unit, or create a new board profile.
5. Set the correct peer MAC addresses in menuconfig
6. Build and flash the firmware.
7. Test audio at short range first.
8. Tune mic gain, speaker gain, channel, and antenna placement.
9. Test range outdoors with clear line of sight.

If your wiring differs, add a new board profile instead of hardcoding changes over the existing black/grey profiles. That keeps the firmware easier for other builders to understand.