We have noticed that few of our customers need help to get comfortable with flow to enjoy the full benefits of creating custom insights. Towards this goal we have started a tutorial series that should help you get started and reach the point of creating a successful custom insight card for the assistant. 

Have a look at https://aka.ms/studiotutorials

We have just posted the first tutorial and will keep posting one every other week if not sooner. Do have a look and share your feedback.