i got a new phone and i am trying to restore the old data from the icloud. unfortunately i set the two step authentication where it requires a code that apple sends to the old phone number which i dont have.

You will need to log into your Apple ID from a web browser like safari and remove your old phone number and add in your new phone number to receive the authentication codes to the right number.

1. Log into your Apple ID here-->>https://appleid.apple.com/#!&page=signin
2. More information on updating your phone number associated with your Apple ID here-->>About two-step verification and SMS - Apple Support

Once you have successfully completed the change of phone numbers then try to restore your iPhone from the iCloud as you normally would.

Axel F.