I've not used this radio
But with the pro if you've got it setup so engine starts on channel 5 on/off you need a rotary know for the sound effects. If you've got this it should be
0-25% = no sound
25-50% = sound 1 (called slider 1 in config file)
50-75% = sound 2 (called slider 2 in config file)
75-100% = sound 3 (called slider 3 in config file)
If your not getting these try running through the radio setup process with dip switch 8 again making sure to active channels 5 & 6 again. Also double check the microSD card for the files. Obviously if files not there it won't play but so often missed.
If your really stuck with the radio drop me a PM and I can ask Scalawag if he can help as he's more knowledgeable
Ian.