1. First, log in to Taobao and click "Qianniu Seller Center" on the upper right side of the homepage.

2． Secondly, under "Common Operations", click the "Baby for Sale" option below, as shown in the figure below.

3． Then, enter the list of products for sale, find the product whose category you want to change, and click the "Edit Product" option on the right side of the product.

4. Click the "Switch Category" option on the editing interface to enter the category selection interface.

5. Finally, change the first-level category as needed. After making the changes, click "I have read the following rules and publish the product now" to complete the operation.