Past Perfect Tense

The past perfect tense should be used when there are two actions. It is used for the action that occurs first.

E.g.1) I brushed my teeth. I left the house hurriedly.
"I brushed my teeth" occurred first, so we should write:
After I had brushed my teeth, I left the house hurriedly.
or
Before I left the house hurriedly, I had brushed my teeth.

2) I did my homework. I went to bed.
Logically, "I did my homework" occurred first, so we write:
After I had done my homework, I went to bed.
or
Before I went to bed, I had done my homework.
or
By the time I went to bed, I had done my homework.