Pinduoduo to upload product materials as follows:

1. Log in to the background of Pinduoduo merchants and enter the "Commodity Management" page.

2. Find the product that needs to upload the material in the product list, and click the "Edit" button to enter the editing page.

3. Find the "Product Materials" tab in the editing page and click to enter.

4. Click the "Add Material" button, select the material file to be uploaded, and support different types of materials such as pictures and videos.

5. After the material is uploaded, you can perform operations such as cropping, rotation, and scaling, or adding text, graphics and other effects.

6. After confirming that it is correct, click the "Save" button to complete the material upload.

It should be noted that Pinduoduo has some regulations on the uploaded product materials. For example, the pictures are required to be JPG, JPEG, and PNG formats. When uploading materials, you should read the relevant regulations carefully, and operate in strict accordance with the requirements to ensure that the uploading is successful and meets the specifications.