Connect the iPad to its Power Adapter and allow the iPad to charge. Then, while still connected to the Power Adapter, 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:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.

If you are experiencing difficulties with the new iPad, try setting-up new iPad from the initial "hello" screen using just your AppleID. At this point, don't attempt to perform the transfer from your source device. Complete the initial setup - and then perform the software update, if needed, from iPad settings:
Settings > General > Software Update
When you have finished, simply reset the new iPad - and then perform the transfer:
Settings > General > Transfer or Reset iPad > Erase All Content and Settings
These support pages should get you started with setup of your new iPad - and the methods of transferring your data from old to new iPad:
Set up your iPhone, iPad or iPod touch – Apple Support
Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support
Use Quick Start to transfer data to a new iPhone, iPad or iPod touch – Apple Support
If the donor iPad, from which you are transferring your data precedes iOS12.4, QuickStart will not be available.
“Transfer” is rather a misnomer. In reality, your data and setup is merely cloned to the new device. Nothing is moved or removed from the original device.
An alternative is to restore either an iCloud or iTunes backup to the new device:
How to back up your iPhone, iPad and iPod touch – Apple Support
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
You would be best advised to keep both your old and new iPad connected to their respective Power Adapter's throughout the initial setup and transfer processes - as this will keep their WiFi active while the processes complete.