You can easily add a video to your archive by giving it a tag.
Click on the video you wish to add in your video library
Click on tags
Select your tags by clicking on choose from available tags
Choose the tag/category you wish to add the video to.
Your video is now published and categorized in your video archive. Could it be easier?
Note. The tag you choose must have been added to the spesific archive under tag management. More info here.