TD6V Backing track triggering

[Biff]

Hi there, new to this forum and sorta new to vdrums, how do I trigger one of the built in songs/ backing tracks from say striking a cymbal pad or other pad?
I've read the manual and found the section explaining it but I'm still unable to figure out the setting to enable this..I've seen it done on many YouTube vids so I know it's possible.
Thanks in advance for any and all assistance.