First, you need to register as a member of Alibaba. There is a supplier portal in the upper right corner of the Alibaba homepage. Click to enter. There is a service portal in the left column. The second item is to post a purchase request. Then select the category of the product you want to purchase on the new page. Click Next and fill in the details. The more detailed the specifications and attributes you fill in, the better. It will be easier for the supplier to contact you.