My handset (Celestron CGEM mount) is not working anymore. I downloaded the virtual Celestron handset, but using it while looking through the viewfinder to align the scope is impossible. How do I do the initial, two-star and calibration star, alignment with NINA?
You don't need to.
Install ASTAP, tell NINA where it is for plate solving, and put in your scope's focal length.
Once you're all connected to your equipment, use the "Manual Focus Targets" tab in the main imaging screen to select a star. Click the "Slew" button to have your scope slew to it. It may or may not actually point to it. Doesn't matter.
Go to the Plate Solving tab. Make sure "Sync" and "Reslew to target" are checked. Click the ">" button to start plate solving.
NINA will take an image, platesolve it through ASTAP, sync the scope to the solved position, re-slew to get to the actual position of the star you slewed to, and repeat until it's within the error set in the plate solving tab.
That's it. You're done. No need to do a 2-star or calibration star or any other "star alignment." Platesolve and sync, and go image.