DBub888,
Saving files in Vectric programs will standard always be in the designated format extension of that program.
You need to create a toolpath (G-code) with the appropriate post-processor for your machine that will work with UCCNC.
After the creation of the toolpath you save this file and load that file in UCCNC. (now you get the correct file extension)
Done.
Align your machine, set the correct X,Y-Z zero positions and check.
Now you can start milling.
Good luck
SC 1/420 + Gantry extension, Kress 1050 FME-P, WinPC-NC USB v3.40,
Vectric Aspire 9, SolidWorks 2021