Hopefully your back up is on the same OS as the new device.

The cord that came with your new iPad should work. It should be a USB C to USB A. The C side (the smaller side) will plug in to your iPad and the larger A side will plug in to your PC or Mac. UNLESS it's a C to C cord then you just need to get an A to C cord, they are available on Amazon.....
https://www.amazon.com/AmazonBasics-...mUvbUpU3107797
For some strange reason the 6 foot cord is cheapest, that will be fine for your needs.
UPDATE: If the included cable is c to c and you just want an adapter I would get this, HOWEVER it don't hurt to have an extra cable. It would also plug in to any other power bricks you may still have....
https://www.amazon.com/Warmstor-Adap...mUvbUpU3107797