You should familiarise yourself with the terms used in this help file first! In particular, you should get to grips with the terms we apply to various sections of the layout in the software so you know what we are talking about!
Some are obvious, whilst others are not.
AirPlayer is the name of the main player at the top left of the screen, which is always inextricably linked to the current playlist.
Command Manager is the name of the object at the top right of the screen, which will at least always display the system time.
Live Source Player allows you to play straight from the line-in of a sound card, and is located under the Command Manager:
Library is the grid that is viewable from the Library Browse tab on the main screen.
Note the distinction between this and the Database, which is viewable from the Database / Search tab on the main screen.
The term database may also be applied to the underlying Microsoft Access database where all the song information is stored, depending on the context used.
Playlist Editor allows playlists to be created, modified, and so forth. Though one may delete and add items to the current playlist (which is the currently active playlist loaded), use of the Playlist Editor is recommended.
Audio Properties Editor is the window through which one may change the various aspects of each playable item in DJ-Serv. You can use this to change artist / title information, set the point at which this song will fade to the next (called the segue point, or sectone), assign an image to the song, and so on.