Readying for Trade-In Problem.

I've followed all the steps required to prep my MacBook Pro for trade-in. After erasing the hard-drive and re-installing the latest OS, I've returned to find a screen that is asking me to "Choose Network". Is this supposed to happen as part of the downloading process is it part of the set-up assistant? I'm unable to shut down using Command-Q so I'm assuming it's still part of the download.

Apple advises: "After macOS installation has been completed, the Mac will restart to a setup assistant that will ask you to choose a country or region. To leave the Mac in an out-of-box state, don't continue the setup process. Instead, press Command-Q to shut down the Mac. When the new owner turns on the Mac, the setup assistant will guide them through the setup process."

At a loss, and would appreciate some help. TIA.