Any user with access to the Content Pool can create new posts from their stock items. To get started, first, click on any stock item to open its detailed view, then click the Copy as post button in the upper right corner.
This redirects you to the standard publishing workflow. Select the channel you'd like to use to publish your post.
Publish will automatically fill in the post draft with your assets. Labels will also be carried over, although internal notes will not.
Note:
If your stock item contains an embargo/expiration date, users will be warned of the intended dates, but may still override and continue to create posts using the stock item.