Varies widely by speciality and even by program. Very different dynamic in a large IM program with 20+ residents a year compared to a small subspeciality with 2 residents per year.
Very broadly speaking though, there is usually a hierarchy and you'll just have to adapt to whatever you find. In general, you're never wrong running things up to people immediately senior to you before taking them up further.
My program was heavily resident-run. Chiefs managed all the vacations, concerns, call schedules, changes, etc. The PD would sign off but by the time anything got to his desk it was usually a finished product and he was an awesome and reasonable guy. After I graduated, the residents decided to shift from a home call to a night float system, and they figured out all the rotational schedules and brought it to the PD and got it approved.
We had a very chill program compared to others and junior residents would often call attendings directly - not every program does that. Even so, attendings want to be called with a plan already made, even if they don't agree with it, and juniors were usually urged to make a plan with their seniors before staffing things higher up. Better learning for the seniors, and spared the attendings poorly worked up presentations from juniors.
You'll figure stuff out when you get there. When in doubt, ask someone senior to you. Try to avoid skipping wrungs of the ladder lest you make someone above you look bad - never a good idea.
