They are examples trying to show what options you have in your implementation, ranging from the simplest use case where all users are hardcoded to the same AWS role, to dynamically setting one or multiple roles based on the user’s profile.
The last example is just showing how you could also add configuration of the session expiration, and could be combined with any of the above.
I’d recommend starting with the first, hardcoded example for your testing, and once you are happy things are working you can make additional changes to the rule to best fit your use case if needed.