Imperfect

Past Perfect The “perfect” or composite past – Le temps parfait ou Passé Composé
The most commonly used past tense in the modern French language. It is used to express an action that has been completed at the time of speech, or at some (possibly unknown) time in the past.
The Passé Composé (Past Tense) is formed with a helper (also called “auxiliary”) verb followed by the past participle of the main verb. The helper verb is always either AVOIR or ÊTRE, depending on which main verb you’re using. With reflexive verbs, the helper verb is always going to be ÊTRE.

Passé composé
Forming the negative in the passé composé

Passé composé of Reflexive Verbs
Reflexive Verbs in Passé Composé (Past Tense)

Verb Tenses
Elements of Grammar