The auction will start automatically at the time you set. Before your auction starts you need to make sure you set it to Public. All campaigns are automatically set to private when they are created.

To make it Public, you'd change the visibility setting from Private to Public in your dashboard. Head to Auctions, Click "Manage", then "Settings", then change to Public. That's it - good to go!

If you would like to watch a video on how to change your auction from Private to Public click here.