Hello - I was just in DR going to Punta Cana in Jan of this year. I didn't fill anything out until the GA at the airport (F9 - ORD) told us during the boarding call. We scanned a QR code and filled out some info. When I got to customs, they already had the info and didnt need anything from me other than my passport.

TL;DR - Dont sweat it. Enjoy the trip.