Ask the senior inpatient physio at the hospital for resources on the ventilators. If they don't have any, then your in a bad place for a new grad. Not to worry though as the nursing staff should have resources regarding the ventilators.
Ventilator's are different so you need to find out which one it is to research it and I suggest just asking the ICU nurse - or nursing clinical educator for information about the ventilator.
If you want to know more about ventilator modes then thats a bit easier to answer but again they can vary between ventilator's... so best to find out specific to the vents they are using.

Good luck. - I got tossed into ICU without much supervision either, it was fun and exciting but I had an amazingly supportive ICU staff and I got them to do the things I didn't know e.g. suctioning while I helped support the patient for example and was able to learn in an active environment.