Hi @whittier-museum. That is odd.
Resume the listing you wish to duplicate. Click the blue "List It" button at the bottom. Once it is active, click the "Sell Now" hot link located beneath the main image.
Now that listing will be saved in your drafts for a template. Then remember end the listing you just activated.
Any change to a draft will reset the clock so keep on eye on the time remaining for your drafts so they don't expire.