You can copy all existing content in two different ways.
1. Open the three-dot menu for the content in the playlist view
2. Select the playlist
You can copy the content to playlists it is already linked to with the same settings.
In this case, the original content is not changed, but a separate copy of the content is made according to the selected settings.
1. Open the content editing view
2. Make the desired changes
3. Save the content as a copy