When there are 2 events in the past, the earlier event uses the past
perfect form of the verb i.e. had + <verb>

Now, there are cases where one has to use "had" in its actual form
i.e. to possess. Sentences involving such a construction uses the rather
weird "had had" verb form to denote that this event happened prior
to another in the past.

"If she had had more money, she would have bought a bigger house"

In the sentence above, "bought" already denotes the past. So, it is
correct to use "had had"

So, If I understand you correctly, if we use "had" only once, then both events would be in the past tense and that would not set up a correct time relation.

So "had had" achieves that.....got it! ...Thanks

Thank you once again JayHawk...Very good explanation