1. Le Plus-que-parfait
is also a past tense

2. Le Plus-que-parfait is a past tense It needs a helping verb
You need “avoir” or “être” in the Imparfait
You add the past participle to the helping verb

3. The Plus-que-parfait Is like the passé composé It needs a helping verb
It needs the past participle
It is a compound tense
It is a past tense

4. Has the helping verb in the Imparfait
The Plus-que-parfait
Has the helping verb in the Imparfait

5. Has the helping verb in the present tense
The Passé composé
Has the helping verb in the present tense

6. The Plus-que-parfait
Is used to express a past action that happened BEFORE another past action.
You could have a passé composé and a plus-que-parfait in the same sentence.

7. Le plus-que-parfait
You could have the plus-que-parfait and the passé composé in the same sentence.
The plus-que-parfait can come first or second in the sentence.
It will not change the meaning.

8. Example Quand je suis rentré chez moi, ma mère avait fini de cuisiner.
When I returned home, my mother had finished cooking.