new ipad wont finish signing in

Something has stalled. A forced-restart should clear the issue:

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.

in rare circumstances the download and installation of associated Apps can appear to stall.

Try a long-touch (i.e., touch and hold) of any App that appears to be stuck; next select Prioritise Download. This will usually kick-start and complete the App installation process.