To follow-sell a product on Amazon without using brand authorization, you can do it by following the steps below:

In the "Inventory" section of the Amazon backend, select "Add New Product".

Enter the ASIN code of the product you want to follow-sell in the search box.

After the search results appear, select the product link you want to follow-sell, and then click "Sell this product".

Since it is a follow-sell, you will share the listing of the product, so there is no need to set up pictures, five-point descriptions, and other information. Just make sure to fill in or select the price, seller SKU, product status, inventory quantity, and delivery channel, and then click "Save".

Please note that the FNSKU code used when following the sale is automatically assigned to the listing by Amazon, and all shipping operations and labeling need to display this number. Through this process, you have completed the process of following the sale of a product on Amazon.