I agree with the above poster - the videos on the SteinAir website are terrific.
Quick cheatsheet - TNC means Threaded (screw on), BNC means Bayonet (slide on, then click in place). Seems basic enough, but it took me two years to figure that out.
A couple of suggestions - use a couple of layers of heat shrink tubing over the final crimps as strain relief. Everything vibrates in a plane. A little extra protection is a good idea.
Second, check that the center pin is long enough for good contact. I spent a week trying to figure out why my GTN650xi lost its GPS signal 15 hours into Phase 1 testing. Something vibrated just right and the pin was just barely making contact, then lost it.