Here's a couple of pictures of Durinish moorland -
That's the Outer Hebrides Isle of Harris on the far horizon.
This is the summit of Ben Corkeval. MacLeod's Tables are ever-present. The deer fences are a bit of a pain, as there are no gates, so the only option is to find a strainer post, which won't wobble, and then scramble over the top!
Here, the display is showing how far I have walked, my precise location (by grid reference in this instance), the time of day, the total time I have been out, and my average moving speed. This display can be changed to show other details, but these are the items I find most useful.
This is the picture I took from NG 19394 45367
Before I set out, I use mapping software on my computer to plot the route I wish to take, and can put a 'waymarker' on places I particularly want to visit - maybe a hill summit, waterfall or whatever. This then gets uploaded to the GPS device. The display can be switched to show the route I have plotted, and as I walk, a track also appears on the screen, so I can see how close I am to the plotted route, and can easily find the waymarkers, as I can see my track getting closer to the waymarker 'pin'.
Once back home again, I can reconnect the device to my computer and download my track and then superimpose it over an OS map display. like this:
Oh yes - and I do carry spare batteries!