Yeah, for lunging, make sure you have a safe, enclosed area. You can start by just clipping the lead rope onto his halter, and using a dressage whip or lunge whip. Tell him "walk on", and if nothing happens, cluck and wave the whip at his butt. Start by having him just walk small circles around you. If he still doesn't go, touch his butt with the whip. It won't take long before he goes from just "walk on". You'll need to get him used to the idea of going on a bigger circle before you do any trot work - that's when I'd switch to using the longer lunge whip. But always, voice commands first, and keep your body position and attitude so that you're making his butt go foward. For slowing back down again, if just "whoa" doesn't work, assume a body position that opposes his shoulder more, and of course, lower or drop the whip.
If it's still mud, I'm sure there are some good how-to vids on you-tube for lungeing and teaching a horse to lunge. Lungeing is really a great start for any kind of training, so good luck with it :)