The above post is a great summary of how you should approach patients in the ED.
I'll add that expectations will vary significantly between EM rotations. At one county hospital, I carried as many as 4 patients at a time, I often did my own lab draws/peripheral IVs, was able to order initial labs/tests, and presented directly to attendings. In a subsequent community hospital, when I tried to pick up a 3rd patient, my resident got upset--students were only allowed 2 max, was not expected to do any blood draws/IVs, I had to present to my resident before presenting to an attending, and couldn't order anything until cleared with the attending.
So just ask... 😀