A good theoretical foundation is good to have, but this does not give you hands on practice to be able to correctly use the microscope, of course. You will have to learn how to center the specimen, focus it and how to switch the magnification (all easy). You also have to learn the correct use of the condenser aperture diaphragm. This can be learned in a matter of a few hours of practice.
The most difficult part is the ability to make sense of the things that you see. For example, beginning microscopists (such as students, who are beginning to learn the use of the microscope) are sometimes fascinated by distracting large round structures in the field of view. “Are these the cells that we are supposed to see?” they ask me. These are air bubbles, but often they think that these are the structures of interest. In short, microscope use itself is easy to learn, but understanding what you see does require some biological knowledge and willingness to read up a bit.