Business rules domain modeling

In our matter management system there is a central concept of event.

Event is sequential, unambiguous numeral encoding the current state of the target entity in it's lifecycle as defined by the business rules. Events accumulates the whole processing history of the matter. For each target type there are dozens of possible events in it's lifecycle.

Events table is by far the biggest table in the schema, reaching a frequency of dozens of millions of rows each year.

Events are the most central concept to control the UI, integration and batch processing flow. The well-documented numerical values of these events encodes major fraction of the business rules based on complex equations and order comparisons of these numerical values and their combinations to derive the next state transitions.

I'm fascinated by this design and the planning process behind it. If I were to design a complex enterprise system, what are my best resources to learn to model and apply such strategic design choices aptly? Is this where the DDD comes in, or where do these architects gain their knowledge?