Andy Leonard has a detailed post on setting up SSIS catalog environments and references:
Why This Complexity?
My argument for embracing (or ignoring) the complexity of SSIS Catalog configuration is straightforward: Externalization – the act of storing execution-time values outside of the object to be executed – is one way to achieve portability, a software development best practice.
As an architect I loathe complexity. Whenever I encounter (or opt to develop) complexity in a software project, I question it. I ask others to question it. I don’t always arrive at the right conclusion, but I challenge complexity at every turn.
I’ve helped several organizations implement SSIS Catalog portability using Environments and References. We all agree that the solution is complex, but most also agree that the complexity is worth the flexibility achieved thereby.
This is a fairly lengthy blog post, full of good information.