Some basic details about your event would have been entered as part of your account you can update the details but clicking on Auction link on the left:
The Auction details page lets you modify the information about the Auction.
The summary tab lets you modify some basic information about the event.
The Event Date field entered here is informational only, it is not shown publicly and is primarily used to sort all the auctions associated with the organization correctly. If you have a long running event you can use the end date.
Under the Advanced section, you can modify the next assigned Item # or Bidder # that will be assigned automatically, but generally there is no need to modify these.
You can upload an auction logo to help customize your event website & emails.
Click on the Images tab and then Upload New Image. See Images for more details.