Is the car actually new or just new to you?
If brand new car - take back to dealer: often high temperature grease, as an extra lubricant can solve this. If older car, may sound like stating the obvious, but check pads/discs/clips etc
'Benign' brake squeal can happen to a greater or lesser extent on some cars - have heard (anecdotally) that e.g. Toyota are more prone than others...but not sure about this
If braking system OK, high temperature grease should certainly help - ask garage