Clinical Performance Exam help!

Hello! I'm in my third semester of a two-year RN program. I have my very last clinical performance exam this coming Tuesday, and (as always) I'm a nervous wreck about it. I feel I performed well all semester during my rotation, but of course now I'm second guessing and questioning some of my skills. Here are my questions... Thank you in advance to those of you who are kind enough to help me out!

The hospital that I'm assigned to uses the Hospira Symbiq pumps. There are two cassette loading ports on each side of the pump, allowing two different tubings to run at a time. My question is.. when hanging a secondary IV bag to an existing primary line, do the bags' levels need to be changed? Meaning does the primary still need to be lower than the secondary? It's my understanding that the secondary line would be ran through it's own loading port, and then attached to the primary below the pump. I apologize if this question makes no sense at all... I'm sure my nerves are getting to me a bit. IV systems have always intimidated me a bit, and I'm almost positive I'll be assigned a secondary line.

I have hung TPN with fat emulsions on these pumps before; each line was ran through it's own cassette and I didn't need to change the levels of the bags. I attached the lipids to the TPN line below the filter and set the rates of each bag separately. I seem to understand the TPN thing, but antibiotics, etc. are what scare me.

If someone has specific experience with these pumps, that would be so helpful to me. Thank you again