Hizpo back up camera trigger wire

Hi I understand how the back up system works where 12VDC is supposed to Tigger the head unit to switch to the back up camera feed. I bought hizpo head unit for my 2008 tundra and I can't seem to figure out where on the head unit the Tigger wire goes into the tundra specific head unit

 

I had this unit and had same question so I emailed the seller and they replied.

There is an orange and black wire that splits into 3 you have to connect the trigger wire from the camera to one of those wires.

This video also helped around 6:30 mark he talks about the back up camera.

https://youtu.be/1xs1UQIt2jE