Motor Home magazine has a yearly dinghy towing guide, it is on line as well I think. The new one just came out this month.
The instructions for the 2019 is to set the brake, start the engine, put the transfer case and trans in neutral, turn off the engine, leave the key on, disconnect the negative terminal on the battery, put the trans in park, make sure the steering wheel is free and the truck is hooked up then release the brake.
My 2015 Colorado is the same, not sure about a 2012.
