Talk with your prof, arrange a meeting and talk to him/her about the project, about what has been done, about what they are going to do. <-- I'm sure you've done that already
I'm sure Dr. McKenzie can help if you find yourself in trouble. I'm working with one of Dr. Berti's grad students and I've got a meeting with the 2 of them on Tues to talk about what I can do for their project. I think it'll basically be similar to our 2L03 and 3L03 labs but different in that we aren't working with our classmates on similar experiments (i.e. class assay). There will, for sure, be something that is applicable to your project from the two lab courses whether it's technique, theory, or experience. There will also, for sure, be a whole bunch of new things to learn and get used to. That's ok as long as you are flexible, which is important in science.
It's really like a research situation (at least for me) in that if something works that's great, if it doesn't it's not necessarily your fault but you would have to scratch your head, stare at the experiment for a bit and figure something out with your grad student/supervisor. Different profs and graduate students have different ways of doing things, just go in with an open mind.
^I don't know if all that BLAH BLAH answers anything... but it's my view on things so far through my meetings with Dr. Berti last term and last week.