To add a new store to your account, look for "Store" in the upper right corner of any page in the app, then click on the arrow to pull down the menu, then click on "+Add Store". Each store will have it's own subscription, subscription start date, contact and billing information if different.
Start by completing the New Store Information, then the Billing Information. Once saved and the store's first month’s subscription is successfully charged, your new store will be activated. To be sure, you will see the store name in the upper right corner next to "Store:". This is where you will also toggle between e-ProductPlug stores.