Oh you don't sew them onto your head, you sew them onto the clips. The clips have little holes on the sides of them... you layer the hair up 2 or 3 layers, then sew through the holes wrapping it around the edge of the hair... I don't really sew either, but it's super simple... easier to show someone then to type out though :S
I found this, this is pretty much how I do it.