I am not an Epix owner, but according to the specs, you can use Garmin Connect for this purpose. It means both Garmin Connect Mobile, and Garmin Connect Web. Garmin Connect Express should work too (useful especially for firmware updates, GPS ephemeris data updates, for route planning, etc).
... maybe I misunderstood your original question. If you are asking how to view the map of the hike you did, then first of all you have to start logging the GPS data before you go walking. In Garmin's terminology a hike, walk, run, etc.. are called Activities. So to start the logging of the GPS coordinates, and to have so the possibility to review the statistics and the route later in Garmin Connect, you have to start the "Activity" (and of course to stop it, when it is over). You'll find the exact way how to do it, in your user manual here: https://www8.garmin.com/manuals/webhelp/epix/EN-US/GUID-90B3EF66-C7DC-4BB5-A1A3-C07E1E9E7A57.html. Once done, and the watch synced to Garmin Connect, you'll se the map on the page of the respective activity (accessible through the Menu » Activitiesin Garmin Connect).
