Thanks for the information. For others, looking there, here are the posts that give a clear picture of what to expect from people that have done it.

When you have completed the travel declaration and testing questionnaire online, you get a QR code that is e-mailed to you. You either print out the QR Code or you display it from your smartphone and a fellow working the exit line in the airport scans the code with his smartphone. Assuming all is ok, he lets you go to the head of the line and the exit. The line is mostly people who did not go online and fill out the travel declaration. They are waiting to go to desks where they have to provide their information to an agent.
- Sept 30,2020

I'm here now. I got a rapid test done at CVS Friday night and flew in on Monday. I just uploaded it to the travel declaration and they just scanned the QR code at the airport and said I was good to go
- Dec 3, 2020

...you are taken to a page that has a QR Code which you print. That code is your ticket out of the airport. If you completed the declaration with any of the testing options completed you get a QR code to exit the airport.
Dec 4, 2020