1. Apply for product showcase: Open Douyin APP, enter the "Me" page, click the "three stripes" icon in the upper right corner, select "Creator Service Center", and apply for opening the product showcase function.

2. Add products: After opening the product showcase, you can add products on the "My Products" page. Click "Add Product", enter the product title, description, price and other relevant information, and upload the product image.

3. Set product display: After adding products, you can set the display method of the products. You can choose to add the product to your profile or add it to your video when you post it.

The above is all about the method of opening a window on Douyin. I hope it will be helpful to you!