Download froze with 4 seconds left. iPad Pro 1 week old.

Are you still able to interact with the iPad - or has the iPad entirely frozen?

If you are still able to interact with your iPad, force-close the settings App - then re-attempt the update:

If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support

If instead the iPad has frozen, perform a forced-restart:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.