Calibration happens pretty quickly. From what I recall there is a message that appears somewhere, but I had it for such a short time with 7.0 I forget where it is displayed.
If you follow the autopark instructions and drive slowly (<18 mph) past a potential parallel- or back-in space, you should see a small "P" icon on the ICD (instrument cluster). If you see that, autopark is ready to go. Stop, put the car in reverse, accept the "autopark" on the main display and watch the car do its thing. I always monitor everything carefully but have never had a problem. Parallel parks works almost as fast as I do and always nails the position. I'm always watch my side-view mirrors like a hawk with back-in (a.k.a perpendicular) parking because it does come uncomfortably close to the cars in the adjacent space before it goes forward and straightens out, but I have never had a problem.
Summon options are on the driver assistance configuration screen. There aren't too many options -- just stopping distance, tight/wide, total distance, and use of auto-homelink.
You can summon from in the car. Put the car in park, double-press the "P" button at the end of the stalk, select forward or reverse on the screen, then open and close your door (you might have to take off your seat belt). The door trick fools summon into thinking you got out.
Hope this helps.