When starting to learn Hexagonal Architecture, you can get easily overwhelmed by all the articles and lectures because they often include a much broader view of the Hexagonal Architecture than the on originally proposed by its author. This view often mixes Hexagonal Architecture with other architectures and approaches like Layered Architecture, CQS, CQRS, and so on.
In this talk, we'll get back to the original idea as proposed by Alistair Cockburn but also take a look at how it can be combined with other architectures and why is it so popular.
https://medium.com/we-are-madewithlove/hexagonal-architecture-demystified-fca986a85b20