In Acquisition mode, you're exploring the world, solving puzzles, and participating in some light combat. You can do things like loot ancient ruins to locate lost books, or get items needed to complete trade quests (to get more books) or items needed to repair damaged books or unlock/uncurse magic books.

Also, as you help liberate and defend nearby villages, once the villagers feel safe enough, they'll start hosting "flea markets" where you can search through multiple vendors pulling from wide arrays of different, often inaccessible loot pools so that no two trips are the same - today you might find two rare books, tomorrow you might find a scroll hinting at the location of an ancient library or a piece of a puzzle key that you need to open a sealed door.