Originally Posted by
Tandem Tom
That might be an option on our older 800 but the Explore 2 I had to do everything through Garmin Express
One difference is the Explore 2 (like other newer units) is an MTP device. The older devices looked like regular USB drives to computers.
MTP is harder to use but you can still copy maps to the device. The following (recent) link has people doing just that.
https://forums.garmin.com/sports-fitness/cycling/f/edge-explore-2/389114/edge-explore-2---osm-map-installation
(Garmin changed some devices to use MTP.)