Lost my iPhone today not sure what to do next

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

AppleCare does not transfer from device to device. It stays with one device forever until it expires or is terminated.

You can look for it using your eyes, or telephone it and perhaps hear the ringing. That’s about all you can do.

Enjoy it!

Next time, be certain Find My is set up correctly.