Loosen the big bolt that goes actually holds things in place. Jack the motor up a little bit on that side, leaving yourself enough room to work. (I just used a floor jack, and a piece of 2x4 up to the oil pan rail.) Jack it up enough that you can get at the bolts for the clamshell. (engine side mount.) Pull the bolts, get the mount out of the way, and the freeze plug is right there. Just drive a screwdriver thru what's left, and pry it out. Use a socket the fits into the new freeze plug nice, and a six inch extension, to drive the new plug in. (put a little RTV around the perimeter of the plug, so it seals up nice.) I drive 'em in just a bit below flush.

Keep in mind, if you don't drain the cooling system really well, (and even if you do.....) coolant is going to come out of that hole........ Be prepared.