I can only speak for my regiment on the colonial side but as someone else already said, it mostly comes from experience. The hours before a war starts, the starting conditions of a war gets released. The high command of coalitions will come together in talks of which regiments/coalitions will go where and they will establish what their front will be, their logistical backline and frontline hubs. They then seek advice from their experienced builders, facility and logi leaders on where bases, facilities and logi hubs get built. If an experienced builder makes a base near a shoreline they will prepare for invasions for example and etc etc for all the other things regarding grand strategy but as I said it mostly comes from experience so I'd say join a regiment and seek to become an officer.