So we just did base game I think? But we didn’t do abbots or the big meeple

Makes sense for a first game. Abbots are optional (though I quite like them, as they allow one to score partially completed monasteries) and the large meeples are from expansion #1 (Inns and Cathedrals).

We did use the river, yes. Is there an option not to?

Yes, you can also use the starting tile, which has a dark back like the river tiles.

no beginner’s luck for me, my brother won, haha

Ah well, there’s always next time! Good luck, and happy gaming!