TradeIT contains a centrally managed set of customer master data, which is updated automatically. All data is imported into your account on demand, for example when an order is received for a new store.
To manually import some customer data use the Import button in the customer master data section.
This will import the current master data for the selected customer and all of its locations into your account. You are free to modify the data if you wish, but this should generally not be necessary.