Random switch question?

We are replacing a switch with a newer model and moving a few people to another building. One of the network admins configured the switch for us.

The new building already has fiber run to it and I've patched the fiber for the new switch. My question is how do I determine which port on the core switch the new switch is supposed to be connected to? I have the switch configs in a text file but have no idea what to look for. The network admin told me the trunk port info should be on the config text but it shows as port 15. That's ethernet and the new switch is using fiber. The old switch was trunked to the core switch with CAT5 cable. The new switch is running from fiber to the core switch if that makes any sense?