Every position is important because you acquire skills and gain experience. Make your progression within the company more obvious by listing separately each position you've held. I haven't completed my education yet. Degree, from University of Sussex, England, is equivalent to a Canadian Bachelor's Degree. Even then, list your experience in chronological order.
Most people use a combination resume.
I have no experience in the kind of work I want to do. Get some fast. Even a brief period of volunteer work will do the trick. Also, re-examine any volunteer work you've done in the past to see if it fits in. Try to combine several jobs into one common area.