Plus-Que-Parfait.
The plus‐que‐parfait (the pluperfect) indicates that an action had taken place and had been completed before another past action took place.
Conjugation:
The plus‐que‐parfait is the compound form of the imperfect and is formed by using the imperfect of the appropriate helping verb (avoir or être) + the past participle of the verb.
Its English equivalent is “had” + past participle.
J'avais mal à l'estomac parce que j'avais trop mangé.
I had a stomachache because I had eaten too much.
Il marchait avec peine parce qu'il était tombé.
He walked with difficulty because he had fallen.
Elle s'était préparée avant de donner sa présentation.
She had prepared herself before giving her presentation
Remember that the past participle must agree in number and gender with a preceding direct‐object noun or pronoun