Believe had the steps in normalization been stressed a bit more with an example it would have become more clear.

Defining A as an entity and B as an entity and identifying the primary identification keys for each is clearly the first 2 steps. Pain must be taken to assure that other dependencies and repeating groups are in fact removed and as necessary, defined as yet another entity and its key.

When this is done you can start bolting all these logical relationships together using the mentioned connector entity and the AB primary keys for A and B.

Good article and sadly, another reason why this used to be several class days with this explanation, examples, and labs. Good job.