Stephen,
You don't need to login to Garmin to "send an event to your watch". This works by saving a copy of the event that you have selected into a special folder for your specific watchId on the MapRun server. When MapRunG starts up, it looks in that folder for the event. (No need to talk to Garmin for this).
However, to get a track from a Garmin watch, the only way is to go via Garmin Connect. For MapRun to get your track from Garmin Connect, you need to login MapRun6 into Garmin Connect so that it has permissions to look at your tracks.
In both cases make sure your phone is connected to the Internet and the Garmin Connect App is running on your phone (as this is the way Garmin Watches "connect" to the Internet).
This document on the website tries to explain the whole process:
https://maprunners.weebly.com/uploads/6/8/6/6/6866500/maprung_user_info_v15.pdfLet me know if you still have problems.
Peter