I have the Garmin 62ST. If your looking for practical advice I offer this.
Take your eTrax for a walk - multiple times (the distance doesn't matter) - and practice going thru the menus until you're at least 1/2 way comfortable with its use.
The GPS language, the terms and usage is strange to the uninitiated plus the arrangement of Garmin's menu is hardly intuitive.
Believe me it will pay you to know how to start and stop a track. And how to store it and how to call it up. Do that now, before you need to depend on your Garmin, not out on a multi day trip.☺