An obvious question to ask would be: how do we build KGs?
KGs have what is sometimes referred to as an organising principle, which is a critical element to KGs, because since KGs are meant to enhance data, giving our data context, the graphs representing this data must be build to follow certain principles [1].
We can think or the organising principles in a similar way to schemas -- they organise nodes and relationships according to the fundamental ideas that are essential in the given use case. These organising principles can range from the relatively simple, such as a product line, or product taxonomy, to quite complex, such as a complete business vocabulary [2]. It can be helpful to think of a KGs organising principle as a conceptual map.
[1] Knowledge Graphs (Ch.1) - Jesus Barrasa, Amy E. Holder, Jim Webber