I would say: "When in Rome, do as Romans do" it's your first day, you don't wanna be the focus of attention, I would prefer to be quieter and observer of the routine your coworkers have. Always be polite, never assume always ask, find an ally and last but certainly not least as in any relationship you're new, don't try to bring on your past experience it's something new you should treat it and enjoy as is and never impose your ideas on your first day, this was the hardest to me