Nikon Z 7 Reference Manual page 362

3
Click Start Transfer.
Pictures on the memory card will be copied to the computer.
D
Transferring Movies
Do not attempt to transfer movies from the memory card while it is
inserted in another camera. Doing so could result in the movies
being deleted without being transferred.
D
During Transfer
Do not turn the camera off or disconnect the USB cable while
transfer is in progress.
4
Turn the camera off.
Turn the camera off and disconnect the USB cable when
transfer is complete.
338 Connections
Click Start Transfer