cant find air tags on my iPhone 13

Just to be sure you didn't miss a step, please review the following support article on how to pair your AirTags to an iPhone: Add an AirTag in Find My on iPhone - Apple Support

If everything checks out, try resetting the tag first: How to reset your AirTag - Apple Support

Finally, to make sure. You mention that they are new. Did you get them directly from Apple or an Apple Authorized Reseller ... or from another third-party source. Regardless, did they have the small tab that you needed to remove to activate their batteries?

If the reset didn't help, it may be possible that they are defective. You will need to check with Amazon on their return policy, but you should consider returning them to get a full refund.

Alternately, you can contact Apple Support directly for further assistance with this matter. To do so, simply select the "Support" link on the lower left-hand side of this forum's web page.