Hi J B! The auction is simple, there is a chat room where you can see the list of upcoming items, and each item will be put in the spotlight for a short time allowing people in the room to place the minimum bid, until the highest bidder wins. The item is not sold if there are no bids, and the creator isnt charged.
To sign up, you make an account (just a standard sign-up process) and add your items, choosing the retail price and the bid price (usually discounted from the normal retail, as bids will potentially bring it up and there needs to be incentive to bid rather than go to the shop). There is a small fee of 5% only if your item is sold (Fee information here:
http://help.tophatter.com/customer/portal/articles/734611-october-2012-fee-schedule ).
Once your items are uploaded, I will send you the auction link and you can submit the items for hosts approval (me, but I will be accepting all items that are entered), and that's all you need to do! When the auction comes around you can choose to stay in the chat room and talk about your piece further than the given description, or you can sit out and the item can still be bid on without you present.
Hope that clears up most of your questions, feel free to ask any others I may have missed.