I am about to install some aftermarket turn signals and brake lights on my mirrors The product is actually VL-20

https://www.kisantech.com/index.php?cat_id=1


I plan on sticking them on the mirrors on the outsides (I have towing mirrors that swing up and out) So when they are out they are on the bottom.

they are actually designed for motorcycles but I would like to have turn signals out on the side of the truck.

So my question is once I route it into the cab where would be the best place to find a)turn signal input
b)brake input
c)power input(with ignition on)
d) ground

I can easily find a ground that's no problem ...but the others ... not sure

thanks