[subject] + had + [past participle]
[subject] + hadn't + [past participle]
had + [subject] + [past participle]?
The past perfect looks back from a moment in the past to something even earlier. You tell a story in the past simple, and when you need to go back further, you use had and the past participle (gone, seen, finished).
Had is the same for every person: I had, she had, they had. In speech and messages it becomes 'd: I'd, she'd, they'd.
Compare these two sentences. The tense tells you what happened first.
When before or after already makes the order clear, the past simple is fine too.
These words often go with the past perfect. Already, just and never sit between had and the participle.
Put had before the subject for a question. For a negative, use hadn't (had not).
Use the past perfect only for the earlier of two past events, not for any event a long time ago.
'd can also mean would. After 'd, a past participle (I'd gone) means had, and a base verb (I'd go) means would.