To understand one concept (Path diagrams in this case) you often need to have learned other concepts that are complimentary, derivative or encompassing of that concept to understand its context and meaning.

To gain this understanding someone might choose many different paths. Three (3) notable ones are:

1. Taking multiple courses that teach the different concepts
2. Read books on the different concepts
3. Search online the different concepts

Each of these ways to come to an understanding are less organized, more time consuming and less positively innovative than 1Cademy.