Hi and welcome to the club!
If we're talking bare minimums to get started, all you should need to install is the Pebble app, from there you can connect to the watch, and you should be good to go (I think there's some kneecapping if you're using an iOS device, but I can't personally speak to that).
The time 2 line of watches aren't really out yet (and I don't have mine yet), so take this with a grain of salt, but one of the best parts of the original Pebbles was that they were watches first and foremost. Out of the box, I could always tell time, get pop ups for push notifications on my phone, calendar reminders, and control my music, which covers the vast majority of my use case. While the app store does have extra utilities and such for the watch, the only one I really remember using was called Find My Pebble- it lit up the screen and buzzed the watch so that I could find it if I took it off (and lost sight of it).
Everything after that is customization, one of the other nice parts about Pebbel was that they had a pretty vibrant community of folks making watch faces, so there was usually something for everyone. Some of my favorites for daily use:
I also remember using TH3 if I was at a career fair and wandered something a bit less whimsical for the setting.