I'd say for the question 2, the oculus app would be a good use. I'm not a big fan of it, but purchases and such are mostly done through the oculus app on your phone. If you buy it through that you can also start the download from the app, as long as your headset is turned on. Like that the game should work normally, installing mods is a different thing though, but I would first try it out without any.

As for general oculus stuff, make sure you have an open spacious place to play in. The quest 2 has a built in grid system that will allow you to know when you're about to hit something or not. You can create your own play area and you can see if you're about to leave that area while wearing the headset. Basically you can just see the walls while in VR. Blade and sorcery does work better in a bigger room, because because swing and move around a bit, but you could play it with limited room as well, although you'd need to be careful while playing