How to communicate a viewing

Hello open-all-hours. If you are happy to do so, you can inform potential buyers that they can view before paying without obligation if they are the winner or purchase the item with buynow. You can't leave contact details in your description or in Q&A

Apart from that have an accurate full description and lots of relevant photos. 

EDIT TO SAY: This is assuming you are talking about a standard marketplace listing. Some items across pets, real estate, motors, service listings do allow you to publish contact details. 

A seller responded to my request to view the product before the auction closes with ‘yes, just email me’, but his email details aren’t published. How do I go about contacting him to arrange a viewing?

Kia ora hoonz3, generally you can't contact a seller to organise viewing before you buy, unless it's a classified or vehicle. We don't allow members to put their contact details on the site. You can use the photos and Questions and Answers to get more information about the goods, we expect sellers to fully and accurately describe their items. If you win the auction and the goods aren't as described you can either not go through with the trade when you go to pick up or contact the seller to resolve the trade. You can even discuss that with the seller in the Q&A up front.