Flight plans created in the MSFS 2020 main menu can be automatically imported into the 'Modern' FMS (and thus used by the LNAV autopilot mode and HSIs) by selecting the FP SYNC option on the INDEX PAGE 2 > MOD SETTINGS page of the FMS to ON. When set to ON, any changes made to the flight plan will also be shown on the MSFS VFR map.

With the FMS option disabled on the EFB, the LNAV autopilot mode and HSIs (with the change-over switch set to RNAV) will always be synced with the MSFS flight planner.

The 'Classic' UNS-1 does not support flight plan imports from the MSFS 2020 main menu, however, it does support imports from SimBrief.