There are many ways to contact suppliers if you are interested in a specific product on Alibaba.com: 

1) Click on either the product listing or product details pages to send an inquiry direct to the supplier

2) Click to  chat with the supplier in real time;
or click // to leave a message

3) Try the phone number and/or fax number listed on Alibaba.com to contact the supplier

NOTE: means the supplier might not be at his/her computer.
    means the supplier might not be able to reply to you immediately