Genealogies are, as I understand them, the way we describe the process of how a problem is solved.
They're a way of thinking about how we come to the solutions we implement, and how and when each step was relevant to getting us to the end.
In essence, imagine a broccoli that was grown from the tickley, bushy end first all the way to that stalk looking thing at the bottom... Except this broccoli is delicious to all ages and not just those over a certain age who have lost their spirit and have resigned their life to eating green, watery plants....
We're getting off topic....
They function in the same way as a family tree, yet a family tree of ideas. You want to start with the initial ancestors of what will eventually become your idea, working your way towards it until finally you have some completed amalgamation of influences and concepts, bringing together one good idea.
Though, the single most important thing to consider when talking about Genealogies, at least as a process for practice, is that each strand, each little brushle of broccoli, needs to made with a problem to solve in mind. Whether it's a practical problem like 'how as we going to keep CO2 emissions down' or 'how am I going to communicate how amazing airwaves, minty-fresh, sinus-clearing gum', these are all problems that need to be solved in one way or another, and Genealogies are one way of working towards the solutions.