I actually bought foundry with the express purpose of using it to run PF2 (since it is touted as being the best implementation) and I haven't had time to learn that either.
The secret to Foundry is that it is EASIER to use the MORE mods you add to it. Assuming you add the right ones.
Start with:
PF2E workbench
anything by the mod maker 'Monk'. <--- This guy/lady/team is basically "Mr Magic Hands" for the PF2E Foundry playerbase.
Pathmuncher
both 'PDf import mods.
Dice so Nice
Dice Tray
Core Settings Expanded
Settings Extender
Combat Enhancements
Cautious Gamemaster's Pack
Module Management
Token Magic FX
Tokenizer
PF2E Dorako UI
Pathfinder UI
(yes you want both of these UIs - they work better when you have one of them overwrite half of the other one. By themselves each kinda sucks. When you have both, a window will actually pop up asking you if you want to disable part of one of them - despite that sounding like it means one of them is disabled... it actually just lets some features of one overwrite the other, resulting in things being nicer...)
Especially for help in learning Pathfinder:
PF2E Modifiers Matter
PF2E Flat Check
PF2E Exploration Activities
PF2E Effect Description
After the above it becomes all about personal preference. But you are better off grabbing any mod that claims it handles some aspect of the rules, or makes it easier to track something.
I also like to have the various animation mods - they make it visually clear when someone has done something, and mods to let me resize windows, make popups of info for players, copy things to the chat log, and so on...
Base Foundry by itself is like buying a toolbox without putting tools in it.
Also, once you have players, I highly recommend listening to them when they ask for or advise you to add new modules. Players who have used Foundry a lot will see whatever setup you have and have recommendations that will almost always improve the experience. It's a great way to learn, and it makes the table feel more welcoming to the group as a whole if the players feel like you're customizing the game to them. You can always turn those mods off in other games you run and thus tailor each game to the exact players sitting down for it.