When and how do you use "Passé Composé" ?

Passé Composé is a past tense used to talk about a completed action that has already been done in the past, something that we know has ended when we are talking about it: "Hier, le garçon est allé à la plage" - "Yesterday the boy went to the beach". This tense is formed of two words: the present of the auxiliary verb, which is always "être" or "avoir", and the past participle of the verb you are using - in the example we used here, the verb "aller" - go. Most of the time, "avoir" is used but "être" is used with some specific verbs- Devenir,Revenir, - Monter, Rester, Sortir, - Venir, Aller, Naître, Descendre, Entrer, Retourner, Tomber, Rentrer, Arriver, Mourir, Partir. An easy technique to memorize them is - DR MRS VANDERTRAMP. Each one of these letters corresponds to the first letter of each verb that "être" have to be used with.When using the "être" auxiliary, the past participle always agrees with the number and gender of the subject: "Les filles sont allées à la plage" - the girls went to the beach. Note the extra 'e' in the past participle to agree with the feminine subject. When using the "avoir" auxiliary, the verb does not agree with the subject, except when there is a direct object complement in front of the verb, in that case the past participle of the verb you are using agrees with this specific DOC.