If Touch Tones will be used to play desired message(s) from the DNA-510A, programming is required to make this happen. 

Keys 1-9 can be "connected to"  a message tone OR recorded message (stored in memory locations #31 through #39)


(The default settings for these locations are listed on Page 6 of the product manual)


For example, 
Program “11#31” to set up the touch tone “1” to play message one.  
Program “12#32” would set up the touch tone “2” to play message 2, 
etc.  

This is described in the product manual at the top of page 7 and Chart 3.