A few notes by Peter Marks, VK3TPM on how to build the source code.
- Etherkit Si5351 library.
- https://github.com/brianlow/Rotary
- Installed Teensyduino from https://www.pjrc.com/teensy/td_download.html
- Via Manage Libraries installed Etherkit Si5351 2.1.4
- Downloaded https://github.com/brianlow/Rotary
- Unzipped it, removed -Master from the folder, dragged the folder to ~/Documents/Arduino/libraries/