This is a YouTube tutorial series by professional anime and game translator Sarah K. She is also a big fan of Sailor Moon and wants to help people learn Japanese through the anime.
Each episode is around 30 minutes long. Sarah plays snippets of the anime and explains each sentence used, one scene at a time. In her explanation, she breaks down every sentence word by word and teaches a variety of interesting points for each. Her explanations are very thorough, accurate, and insightful. Sarah's lovely personality also makes the video more fun to watch.
This is a godsend, not only for the Sailor Moon fans, but also for many Japanese learners who like to study using popular media like anime and TV shows, rather than textbooks. Very useful and super enjoyable. You should give it a shot!