The 645 have bread crump map and you can do Live Track on it right?
Its one of the screen to add to it?
How do I see it on my watch?
The navigation screen will be added automatically. See here for using navigation. www8.garmin.com/.../GUID-64F677A5-03E0-453F-BFE3-E1B93D6FA3FC.html
Livetrack setup is via the Connect App not on the watch. See here support.garmin.com/.../