How do you eat an elephant? One bite at a time, right?
That one-liner serves as a metaphor for how an incredibly complex task can be accomplished by stating a goal, gathering facts, initiating action and formulating an overall plan from a series of achievable objectives using available resources.
That also describes how the U.S. Army Corps of Engineers conducts a feasibility study for prospective projects, though we’d work hard to avoid harming an actual elephant.