"He put on the black coat."
Translation:Il a mis le manteau noir.
etre is used for all reflexive verbs and few intransitive verbs like aller, venir, devenir, tomber, monter, entrer, rentrer, descendre, partir, arriver, rentrer,
I don't understand something. When we use avoir and when être for making passé composé in French?
être are the forms of to be and avoir of to have. so it depends on what you express in your sentence. - i was... - je suis (+ PC) - i had... j'ai (+ PC)