When a person wants to attain a deep understanding of a given subject, he should start by gaining a sufficient overall picture of the entire subject from beginning to end and then go into the details. The reason for this is simple: the end goal of the completed project is present in the mind from the very outset, and all the early stages in the execution of the project are carried out in accordance with the initial intention, which is directed to what is to come later. If so, it is impossible to understand those initial stages and their purpose except through knowing what comes after them, since their purpose is to lead to what follows them. This applies to every stage until the execution of the project is complete, for everything is done for the sake of the end goal.