You can sell items in the Auction House by clicking on an item in your Inventory or Safety Deposit Box and selecting the “Put up for Auction!” option. From there, you will be able to set the starting bid, minimum increment, auction length, and privacy options.
Alternatively, you can also set up an auction at the Auction House page itself! If you click on the “+New Listing” button, you will be able to select the item in your Inventory you wish to auction. Once you’ve confirmed the item, you can set the starting bid, minimum increment, auction length, and privacy options.