Read the course sequence
Check whether the lesson belongs to a series and what the teacher expects you to know. A polished combination at the end of a trailer can conceal several earlier chapters of explanation. The contents list is a better guide to the course’s scope.
Use a teaching sample
Watch a sample with instruction, not only music. Notice whether the teacher explains terminology, repeats demonstrations and keeps the relevant movement in frame. Captions can help with unfamiliar vocabulary, but check them against the spoken explanation.
Keep an observation, not a verdict
Note what you found clear and where you need help. A recording cannot give feedback on your own execution. A teacher can help choose an appropriate level and explain what to work on next.