SnOwball, to break down a recipe into steps, go through the process of executing it mentally at first. Then see which part of the recipe can be grouped together into logically distinct steps. I don't think that there is a rule to apply on every recipe indiscriminately and without your participation in thinking things out.
In the case of Moussaka, and assuming that the link you gave (which I cannot assess) follows the classical recipe more or less, I would break the whole process down into the following steps:
Step 1: Weigh, wash, slice, fry the eggplant (and/or other veggies your recipe may call for) and set aside to drain on paper towels.
Step 2: Prepare the meat mix that you alternate in layers with eggplant and set aside.
Step 3: In your baking pan, put together the Moussaka by forming alternating layers of fried eggplant and meat mix and put aside.
Step 4: Prepare the bechamel sauce in a suitable pot and pour over the Moussaka.
Step 5: Preheat oven and bake as per instructions.
I do believe that common sense alone is what is needed to outline such steps in any recipes. For your next one, try yourself. I am sure you can do it.