From the left side navigation menu, click on Users: Users. This will display a list of all registered bidders and consignors.

To add a new consignor, simply click on the green colored 'Add' button in the upper right section of the page. In the pop up window, the first box is the Role. Use the drop down menu and select 'Consignor'. Fill in the required details and click the 'Add' button to save. Doing this will send the Consignor their username and system generated password they can now use to login to their public Consignor profile page.

Note: Administrators can make a bidder also be a consignor (both roles). They can also make a consignor become a bidder. From the Users page, the far right column, the Actions menu...click on that and you'll see options to make a Bidder also become Consignor or make a Consignor also become a Bidder.