Select the 'Playlists' tab.

Select a Playlist Name (don't tick the box).

Under 'Publish to Signs', select 'Actions' and 'Add Signs'.

Tick the boxes of the Signs you wish to send this playlist to.

Note: a playlist can only be published to signs that have exactly the same pixel width and height. This is to avoid the incorrect-looking playlist content that would appear on signs of a different width and height.

Select 'OK'

Save, Approve & Publish the playlist