I have been a preceptor for quite a few new grads and I'll tell you what I do with and expect from my orientees. I let them shadow me the first day and let them see the flow on the unit and how I manage my time. Then I start them out with 1 or 2 patients to let them start getting the hand of their own flow and time management and advance them to more patients as appropriate. Throughout the day, I ask them lots of questions about the meds they are giving, what responses they expect to see from the patients, other critical thinking questions. I also expect that they will know about the meds that they are giving and the procedures/tests that they are prepping patients for/sending pts to or that they will look these up independently prior to giving the med/getting the patient ready. If it is a time crunch (example getting pt ready for an emergent cath/CABG) I just jump in with them to get the pt ready and explain to both my orientee and the pt as we go and discuss it more in depth with my orientee afterward. Your preceptor will probably do the same with you. If you don't get this kind of feedback/interaction from your precptor, talk to your preceptor about your needs and if the situation doesn't improve, ask your manager for a new preceptor. It's your job, your license and ultimately the health of your patients-protect them.
If you want to set yourself up for success, I recommend getting very familiar with the meds that are common on your floor and the lab/procedure results that you will be seeing often. Also don't be afraid to ask questions! For the safety of your license and the safety of your patients, ask anytime you are unsure of something. Even if you are at the end of orientation or off orientation and it's a med/procedure you aren't comfortable with, ask for your preceptor or another nurse to come in a double check behind you. I still do this and I've been a nurse for years and have precepted many new nurses.
Best of luck!