How do you plan to do the audio?
Have a speaker attached to the pi?
Are you trying to sync the audio to the lights? (if so, good luck with that)
You probably will need an amp of some sort and it is easiest to buy a hat for the Pi. I just happened to finish a project of building a music player on a Pi Zero W using a (HiFiBerry Mini amp -https://www.hifiberry.com/shop/boards/miniamp/).
The music is stored in a folder on the pi and plays one song after another till it reaches the end, then it starts again.
If, on the other hand, you want different sound clips, like an engine starting, a horn beeping, tires squealing you could use some of the same ideas.
Put the sounds (wav files) in a folder on the pi. Use node-red-contrib-play-sound to play the sounds. You may find this writeup helpful (https://github.com/MattVador/node-red-contrib-play-sound/issues/6) which I wrote when first using the node. One thing to note, I would only use one copy of the node in your flow to make it easier to keep straight.
Then just build your flows. I have another flow that has a PIR embedded in a skelleton's head. When it is triggered, it plays a sound and runs some servos to move the jaw. NOTE: If I remember correctly, you can't use PWM and sound at the same time becasue they both use the same peice of hardware. In the skelleton I just used two Pi Zero W's and had them passing messages with MQTT