In my personal point of view, it is too soon to be using a box squat. Focus in on good raw form.
By good raw form I am talking about breaking at the knees and not at the hips. The breaking at the hips is designed to gain more from your gear as an equipped lifter. While some raw guys will break at the hips first, its my opinion not the best idea.
As far as box squat goes, I would avoid it as a new lifter. While it can have some carry over, you would find benefit from doing squats with various stances rather than a box.