Looking for grandparents

[Rain]

hello. I am seeking my grandparents and do not know where to begin. They were born and lived in Rio Pierdras last. However I can not get a marriage certificate on their marriage beacuse I do not have birth dates. I have tried using my fathers borth date but no help. My grandmother is Olga Ocasio Vasquez and my grandfater Juan Vasquez. Their sons name was Antonio Vasquez. I sure hope someone can direct me so I can get some info. Thanks