I need to know how to change coolant in my Stang.

It might sound silly to others but I have no idea how to change the coolant. Never done it before. The car has 51K with the same coolant from the factory. It's weird buy the coolant still looks good. But I don't trust it. Where are the drain plugs? I know there has to be one somewhere in the radiator but what about the engine block? Also how much water and coolant am I suppose to put back in. I know it's 50/50 mix but how much exactly is 50/50 mix. How many gallons of water/coolant. I need to know how many gallons of coolant I need to buy. Also what kind of coolant should I buy? Prestone or Motorcraft? Green or Orange?

Sorry for asking too many ?'s. I just want to make sure I do it right and save some money for doing it myself.

Thanks in advance.

Will that remove all coolant from the radiator and the block? I want to make sure all the old stuff comes out completely.