Login to Back-office > from the left menu go to ‘Settings’ > click on ‘Admin Settings’ in the submenu of ‘Settings’ > select ‘Assign Supplier to Shop’ tab > assign your store as a supplier in drop down of ‘Select Supplier’ option  > select retailer store in drop down of ‘Select Retailer’ > as the last step clicks on ‘Save’ button to assign your store as a supplier. ( my store supplier to B2B retail customers)