I am trying to set up my new iPhone mini and when trying to transfer data from iPhone 8 it keeps reverting to the start

Hello Newphone1706,

Thank you for reaching out to Apple Support Communities. We are happy to help you!

We understand you are wanting to transfer your data to a new device, but have not been unsuccessful. We'd be glad to help out. Sounds like you may be using Quick Start. If so, check out this article for details regarding this process: Use Quick Start to transfer data to a new iPhone, iPad, or iPod touch

"To migrate your data wirelessly, keep your previous device near your new one throughout the process as you follow the steps below. Make sure to keep both devices connected to power.

Keep your devices near each other and plugged in to power until the iPhone data migration process is complete. Transfer times can vary based on factors such as the connection type that you're using, network conditions, and the amount of data being transferred."

You may also need to review this article after Quick Start completes: Finish setting up your iPhone, iPad, or iPod touch

Cheers!