A horse this young shouldn't do very much lunging , IMO. But , teaching him to step away from you, back away from you, move his shoulder away from you; these are all good skills to have. They can be done step by step, little by little.
In lunging, a lot of people have trouble getting the hrose to NOT face them, so they can get them to move forward. I think I wrote a prett long and fairly good (if I do say so myself) response to that question here: lunging issues
I also made a short video about this, though it is a very poorly made video and might not be so great for a real young horse who doesn't already know how to follow the feel of a leadline. Here it is: How to get your horse away from you so you can begin lunging him around a circle