Could be they need to bedded in properly, maybe not enough anti-seize compound was used on re-assembly and so on. What follows is what I do every time I change brakes on cars.
Take it for a drive on a quiet road and progressively put heat through the brakes, not hard braking to begin with just enough to build up heat in the system and don't stop. All we're interested in doing here is generating some heat.
Drive a wee bit further without braking, then give the brakes a work out from speed (legal speed, obviously) down to walking pace but keep rotating the wheels - do not stop fully with your foot on the brake pedal.
You want to go from speed down to walking pace several times, don't be frightened to get some heat in there. If you get some brake fade, smoke, 'smelly' brakes the time has come to ease off and cruise home. Your work is done and the brakes have been bedded in.
I'd be surprised if the brakes still squeal after that work out, but they might depending on who fitted them and the quality of the parts.
So who fitted them and what did you have fitted?