Although still in its infancy, there is already a lot of good resources out the for Mapping Data Flows in Azure Data Factory. I will try and keep this post updated as more blogs appear.
Mark Kromer: https://kromerbigdata.com/tag/mapping-data-flows/
Cathrine Wilhelmsen: https://www.cathrinewilhelmsen.net/tag/data-flows/
Azure Documentation: https://docs.microsoft.com/en-us/azure/data-factory/concepts-data-flow-overview
SQL Player: https://sqlplayer.net/tag/adfdf/
List of videos: https://github.com/kromerm/adfdataflowdocs/tree/master/videos
Hopefully this is a useful reference, let me know of any more in the comments.