Did your Suburban come with them?
I went and asked Chevy/Cadillac here and GMC and they said that there's a main harness (which I've seen before, it's HUGE) that runs under everything except the shell of the car that the running boards tie into. IF you have them. If not, they have to take the whole car apart to install them which could take who knows how long.
They said it's an even harder job than installing power-folding/heated captain's chairs in a Tahoe/Suburban that wasn't equipped! Must not be fun.
mine did, yes. And for a dealership to do the work, yes, I am sure they said its labor intensive because they would install them to factory specs...i.e., harnesses, reprogrammed BCMs, etc.
But, you do not need all that. You just need the steps and a way to wire them into the vehicle so that the retract when the door closes and step out when the door opens. Nothing else would be needed, presumably.