In the beginning, when you first join and enter the Catacombs, you will be completely clueless. You're lost, you have no idea where to go, and you have no idea what kind of people are here! You're new in town.
You can wander around, introduce yourself to the business owners and other people, or whatever you want. But don't be surprised if you get glares and suspicious looks. Typically, the newer you are, the more clueless and ignorant you will be, which can tick off the 'Combs members.
It's like going to a new school. You know absolutely no one and no one knows you. Only in the Catacombs, we don't learn shit. c: