What Had Already Happened
The past perfect expresses an action that had finished before another action took place in the past. The past perfect is often used to provide reasons for making a decision in the past.
Had you discussed appreciation with Tom before you mentioned it at the meeting?
Had they declared this account overdraft to the lawyer prior to the verdict being read?
Did you gather all receipts before getting the final balance?
Subject + had + past participle + (object(s))
I had already agreed to the terms before they offered the additional collateral.
Subject + had + not + past participle + (object(s))
They hadn't come up with enough votes before they protested the bill.
(Question Word) + have + subject + past participle?
How long had you told her to be held responsible for her own account records before she asked for the promotion?