The audio CD plug-in (in_cdda.dll) is installed disabled by default because most new computers are now sold without a CD drive as standard equipment.
Anyway, access to a CD drive (internal or external) is via the media library (so you need to install and activate the plug-ins needed for the media library). You select your CD drive in the library panel on the left and the tracks on the CD are displayed in the library panel on the right. Some metadata for each track is also listed if the CD is listed in the online database that WACUP uses. The search for the tracks' metadata should occur automatically. There is also a command to force a search if needed. If metadata is found it can be stored locally so that it doesn't need to be looked for again, the next time the same CD is used. The locally stored metadata can be edited.
A CD's tracks are selected and played using the same methods used to select and play any of the other files listed in the media library.