Hopefully you can make a fantastic cup of tea. There is skill to it, believe me. You would also be amazed at how many people really appreciate a quality cuppa. They will thank you for it. In so doing you have a great opportunity to make friends, make sure you are able to get names right, put people at ease and start building relationships.
You can't go straight up to the boss and ask who really runs the show around here, however, make a few beverages, get to know people, gossip, banter, have a laugh, share some great jokes and, before you know it, you will be privy to pertinent information. You are straight onto 'water cooler chat' and that is that.
Just do what you can to break the ice, and, best of luck with your new job!
P.S. You are allowed to ask the same question about something three times. Any more than that and people will wonder if you are retarded.