Hi Innodrive only works if you have put a destination into the nav system - i guess on the basis that the car needs to know where its going to anticipate the road ahead!I have Adaptive Cruise Control and Lane Keep. If you have these two, you don't really need Innodrive which uses the contours of the road (mapped) to maintain speed and turns. The ACC and LK will keep you in lane at the set speed. It will sense the car ahead and slowdown or stop accordingly - but you need to keep your hands on the steering wheel at all times or the car will complain - no Tesla auto-drive here.
To turn on ACC, you go to Page 36 of the Taycan operating manual. Turn on the switch at the end of the left hand lower stalk behind the steering wheel.