1991 Buick Skylark loud squealing noise when starting car a

First thing is buy belt dressing at auto parts store might be to dry. Also check belt for to much wear and u should remove it and check all pullies alt water tentioner etc check by turning them to see if they r to tight possible one or more pullies are freezing up, never know right>?Start by spraying belt dressing first on belt. Then go from there. But yes most likely ur squeling is coming from bad belt dry or any one pully bearings r goin bad. Simple work. Good luck