How do I connect my phone to my parrot A.R. drone 2.0?

Follow the drone's instructions, they have they have the steps to connect the phone to the drone. You probably need to download a specific App from the App Store too. To find out which one, read the drone instructions and download the App it requires. It probably has a QR code or a link for the download.

See here: link-> Parrot A.R. Drone 2.0 user guide - bhphoto.com

Free Flight A.R Drone App on the App Store

If you are experiencing any difficulty with third-party apps then please contact the app developer directly --> How to contact an app developer - Apple Support