Have a question about a listing?  

As a Buyer, when viewing the listing details you will notice the "Q&A" tab at the top of the screen. (See Below)  Navigate to this tab and select "Ask Question".  Once you have submitted your question the Seller will be notified and prompted to provide a response.  Once the Seller responds the Buyer will be provided the response. 

As a Seller, you will be notified when you receive a question about one of your listings.  Once you respond, the Buyer will be notified that a response has been provided, and the question along with your response will be added to your listing for other potential Buyers to review. 

Should a Seller want to remove a question from their public listing you simply select the delete button for that specific question and it will be removed. (See below)

Below is a screenshot showing an answered question as posted within the listing details.