The Fly-RRF-36 can be purchased from here https://s.click.aliexpress.com/e/_Dm7ZASH
This link is affiliated URL. If you purchase via link above it will give tiny cent of commission to the community organizers. (We are not Mellow employees, just 3D printer enthusiasts) This will not hurt your wallet and at the same time help us to maintain the GitHub better.
More information on using the board with RRF can be found here https://teamgloomy.github.io/fly_rrf_36_general.html