In general, the processors pass the fish to the trading company (who speak English and have experience managing the overseas market), but certain processors export by themselves, and they typically hire someone who speaks English.
When the orders come in, the processors check the stock, size, weight and ask middlemen to buy from the farm if more milkfish is needed.
For the domestic market, the fish goes to the market directly (does not necessarily goes into processing), but fillet products are processed.
Sometimes middlemen buy fish from multiple farmers to deliver the fish to processors.