I can't find the work when I search for it.

"Add creations to the shelf" only shows creations that creators registered on Zindies have made public. If a creation does not come up, the creator may not have registered it on Zindies yet. In that case, the quickest way is to ask the creator to register it. Creations the creator keeps private do not come up here either. If you would like to add one, ask the creator in a Contact Note whether it could be made public. Stock and prices can be adjusted from the shelf afterwards.