Hi All --
After an agonizing period of weeks during which my brand new EQ6R-Pro didn't work, I have finally resolved the problem by replacing the motor board. Before, no communication with EQMOD, NINA or anything else. Now, it works perfectly. Today I was able to successfully connect NINA to my camera, my guide scope, and the mount.
So, as a total newbie, I'd love some suggestions for a first target to image, as well as any settings like ISO, length of exposure, and so on. Here are my particulars:
1) Location: Vermont, rural, bortle 3 on a good night
2) Telescope: AT72EDII w/ Televue .8 reducer flattener
3) Mount: EQ6R-Pro
4) Guide Can: ZWO ASI 120 mini
5) Camera: Canon DSLR 77D
6) Software: NINA and PHD II
Thanks for all the support, advice, and suggestions.
Cheers, and clear skies!