How are endings formed for past participles?

If the participle is linked to the verb "être" or used as an adjective, its ending is associated with the gender of the subject (add an "e" for female), and the number of subjects ("s" for plural). If the participle is linked to the verb "avoir", it is necessary to consider the place of the participle relative to the verb's direct object in the sentence. If the participle is located before the direct object, the participle receives the masculine ending. If it is located after the direct object, its ending is formed by the rules of the "être" verb.