English and ESL Instructor
The simple past looks like this:
I finished my homework.
A tree fell down.
The past perfect for the sentences above would look like this:
I had finished my homework.
A tree had fallen down.
The past perfect is essentially the verb had followed by the past participle, which in the examples above, are finished and fallen respectively.
When indicating a past action, we use the simple past tense, but when we try to show that an event happened before another event happened, we use the past perfect tense. In other words, the first event is the one in the past perfect tense:
Jared had saved his work before his computer crashed.
Lisa had completed a degree in psychology before she went to law school.