IAPs on App Store Connect: For in-app-purchase review, what does it mean to upload binary?

I added several in-app purchases to my project on App Store Connect, and it rejected them saying Please upload a new binary. I don't know what upload a new binary means. I've uploaded builds to TestFlight, is that all they're asking for here? Do I just upload a new build to TestFlight, and then they'll review and (hopefully) approve the IAPs, or do I need to notify them somehow?

They are just asking for you to upload a new build. A "binary" in this case means the app binary (an app build).

The new build must have the in-app purchase products actually available and visible for Apple's testers so that they can try out the purchase process in your app.