Hi guys, it's been a while since the first time I played the guitar, it was a wonderful experience for me.

I am still a bit confused about the Core learning system. So Mr.Mouridsen is the main instructor in Rock style level 1 and 2, but at the same time, I found a lot of other lessons from other instructors such as Mr.Andy Gurley or Mr.Christopher Schlegel, etc. So, why are these lessons are not included in the Rock style level 1 and 2, and how do I know if I need to learn the lessons of other teachers? And when? (Similar to other genres, not just Rock)

I'm sorry if my question sounds obscure but I think you get the point. And much appreciate your replies guys!