Properly Winterizing Your Truck-Do You Know How?

I've seen people plug in their trucks before but I've never done it. It something about keeping the engine block warm? I searched for a plug cord hiding near my front bumper and found nothing. Possibly a trip to the dealer would give me some answers. In the meantime, I did a little research  and found out there are all kinds of things to do to keep your truck in good working condition for the winter.

I have a Diesel Truck so mine is a bit different I think