There are different kinds of people, some might learn by going the theoretical path you described (functors -> monoids -> monads). I am not one of these people.

There are different kinds of people, some might learn by going the theoretical path you described (functors -> monoids -> monads). I am not one of these people. I learn theory by doing thing in practice. I recommend starting out with IO and "learning monads" as you go. Too many people think they must "understand" monads first, but this might not be the right way to go depending on the person. "Guess the number" and other examples from Imperative programming 101 make great exercises.