To load a pilot route in the UNS-1:
Press the [FPL] function key to call up the flight plan page;
If there are fewer than two legs on the flight plan, a "COPY PLT RTE" prompt is present on the FPL 1/1 page; Otherwise, Delete the flight plan and insert your departure airport.
Select the COPY PLT RTE prompt (LSK 4 Right), then pick the route you want in the list
As Pils said, the FMS just reads whatever is in `X-Plane/Output/FMS Plans`, and that's what will be listed on that page