YouTube Playlists: How to autoplay a playlist in Youtube
For convenience, I’ve copied the following from In Playlists you can't copy a Public list
How to change a public playlist to a private playlist:
- Select the playlist you want to edit.
- Select the three dots icon in the playlist.
- Click the Edit playlist button
- If you scroll down, edit the public settings and click the Complete button at the top right of the screen.