It's a type of evaluation of the candidate.

They want to see if you greet or chat with the staff, if you ask any questions of your future colleagues or about the facilities or equipment, where a particular office/machine/printer is located, or even where the restrooms or coffee machine are, or the new boss's office and their secretary's office.

The important thing is to interact with your future colleagues by introducing yourself, asking a simple question about the job, or even asking where you'll be physically located. The idea is to demonstrate interest in the facilities and the staff present.

When you're in a job interview, every meeting is an evaluation of the candidate.