Since this is about Geometric Algebra, here are two other (complementary) great intros:

* Why can't you multiply vectors? - Freya Holmer - https://www.youtube.com/watch?v=htYh-Tq7ZBI&t

* A Swift Introduction to Geometric Algebra - sudgylacmoe - https://www.youtube.com/watch?v=60z_hpEAtD8