My Hair Is Dyed Blond But Want To Dye It Brown With A Colour Box What Do You Recommend?

I would be very careful with color correction.  It depends on whether or not you are a "cool" blonde, a "neutral" blonde, or a "warm" blonde.  When you bleach your hair, it takes the color pigment out of your hair, including the red.  If you attempt to recolor your hair brown, without putting the appropriate amount of red back into your hair or without using a filler, you may end up with a "muddy" brown or ashy color.  I would seek professional help for the color correction.