Hello,
Playlists consist of a list of entries, as such, they can contain video, audio or image entries.
As you can see here:
https://developer.kaltura.com/api-docs/#/playlist, you should use playList.add() to create a new playlist:
https://developer.kaltura.com/api-docs/#/playlist.add
The entries to include are set in playlistContent, XML if the playlistType is dynamic, comma separated list of entry IDs if the playlistType is static or url if the playlistType is mRss
To update a playlist you need to use https://developer.kaltura.com/api-docs/#/playlist.update.
To get a list of playlists you need to use https://developer.kaltura.com/api-docs/#/playlist.list which will include the playlist IDs, names and plenty other attributes.
To get a list of entry IDs a given playlist consists of, you need to use https://developer.kaltura.com/api-docs/#/playlist.execute.
There are code samples that illustrate how to use playlist.execute and generate a player embed from the list here:
http://player.kaltura.com/docs/ServerSidePlaylist
They are in PHP but the idea is the same for all client libs.