Dive into a comprehensive video tutorial on Power Query's M Code, exploring its fundamental concepts and advanced techniques. Learn to edit M Code through Applied Steps, Formula Bar, and Advanced Editor. Understand expressions, including 'let' expressions, and how to add comments. Explore various data types like primitive values, lists, records, tables, and functions. Master lookup operations, including Row Index and Key Match lookups, and grasp the importance of primary keys. Discover how to create custom functions and implement parameter queries. Gain insights into the underscore character's usage in M Code. Access provided Excel files and PDF notes to enhance your learning experience and practice your newly acquired M Code skills through assigned homework exercises.