The specific steps for merchants in Douyin stores to pay customers using mobile phones are as follows:

1. Douyin merchants enter the store backend, click on the store-interface authorization-apply for authorization in turn, select erp type-other in the pop-up window, and you can get the appKey and appSecret. Then fill in the obtained appKey and appSecret into the store manager to bind the store to the tool.

2. In the background of the store manager, merchants can see the order data. Select Express Template-Orders to be shipped in turn, find the order to be printed, click Print Express Order, and print the order after confirmation.

3. Filter the printed orders in the background, check all orders, and click Ship, and the order number will be synchronized to the store backend.