La ventana est roto. La casa est sucio. Carlos est gordo. Some adjectives are generally linked with ser and others with estar . It is helpful to learn these.
Some adjectives change their meaning depending on whether they are used with ser or with estar.
There are some clear rules on when to use ser and estar in certain cases. Once you learn the rule or use, you should not have any problems. You just memorize these rules. Ella es mi compa era de clase. Carlos es professor.