Please follow these steps to setup flDigi to use DigiLink Nano.
Start flDigi and select Sound Card from the Configure menu to change audio settings.
On the Devices tab, set both input and output device to USB Audio CODEC (macOS) or to the name you set in the Windows Setup.
Leave the defaults values on the Settings tab.
On the Right Channel tab, enable the option PTT tone on right audio channel if you would like to use DigiLink Nano's built-in VOX circuit or disable this option if you prefer to use your radio's VOX logic.
That's it, you can now use flDigi to make contacts.