Plug your fieldmixer in the camera and you don't need a clapper board, other than for being interesting and look very professional!!!
When you have a camcorder with decent audio inputs (XLR with 48v power) you can use a boom pole with a directional mic. and a windshield (you know, those grey fluffy things

)
A lavalier is a good option to, because of the closeness to the speaker, but the problem is that lavaliers is that they pick up the wind quite hard... So you'll have to use a wind shield for that as well. Not a pretty option given the fact that it looks as if your subject has a dead mouse on his chest, but in this kind of educational video's my take on it is that the quality of your voice over is more important then having a windshield on the chest....