Students post their questions via the Web form on the third tab. They also provide links to any ancillary information they believe is relevant. The Prof takes that information and uses it as the start of a blog post. Then The Prof provides a response that might be plain text, perhaps include a diagram or other support visuals, and might also be a short video.
All students, the student posing the question initially and any other student as well, can ask follow up questions using the comments area in the blog post.