Once you are logged into the DiamondBistro, if you click on the "my active listings" button, then from there you should see a menu bar featuring the options of Title, Current Bid, Sold? and Statistics.
Click on the 'Manage This Listing' button beneath the item you wish to edit. From there, there is a button that looks like a white square of paper and a pencil, click on that to edit the individual listing.
If you are already logged in, this link should take you directly to your items for sale: https://diamondbistro.com/index.php?a=4&b=1