With subtitles it's pretty easy... audio files, I don't know how to do.
; Begin
TitleText ["text here","plain down"]
~5
TitleText ["text here","plain down"]
~5
Titletext tells the software that you're making a subtitled sentence. "plain down" means that it will show up at the bottom of the screen.
~5 means five seconds of screen time for the message that went before it.