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So don't worry so much about how to use  had had  as a unit of grammar, they will come together naturally when you want to express the verb ' to have ' in the past perfect. Let's consider a different verb for a moment like  to want .
Would have + V3 is similar to could have and might have but would have is more about something we chose to do or not to do in the past because a certain necessity was not met. Something was missing and that we chose to do what we did and that would have is usually combined with if clauses.