Short, simple, and to the point: How to make join tables.
Michael Rocharde tackles two issues: videos that are too long and windy, and an explanation of join table in about 5 minutes:
I just found a 32 minute video (about 27 minutes too long) on creating a Join table. Here is a simple 5 minute one explaining what is a join table, when it is needed and how to set one up.
Simply put, join table allows you to make and manage Many-to-Many relationships, often found in solutions with educational institutions (for one): Students take several classes, and classes have multiple students. A One-to-Many relationship won’t work for this type of relationship. Learn how to set up a join table at the link.