Is expecting students to learn through inquiry, asking too much?

My L3 Biologists appear to be swamped in learning and it's not a pretty sight! The research essay that they are currently working on asks them to do two things. Learn new, relatively unfamiliar, content knowledge and do this through the process of inquiry. They can't seem to juggle these two balls at the same time (not enough working memory!). It is very clear to me that they have no idea how to plan their research. Even after 4 weeks some are still struggling with identifying the focus question and I don't think this is down to my lack of guidance.

What does it mean to do "inquiry learning"?

This question should get things moving ...