The Past Perfect is used to connect two past times: a previous past time with a later one. In practice it is used to talk about events that happened bafore a certain past time. For example:
- When I arrived, the plane had left. - Before I left (past time), the plane left (previous past time)
- Before I went to Canada, I hadn't been abroad. - I went to France (past time), and before that time I never went abroad (previous past time).

The Past Perfect is made with had and the past participle. For example:
- I had eaten
- She had played
- They had flown
and so on.

As mentioned the Past Perfect connects two past times: a past situation and another one before it. There are few rules, so here are some examples to help you see how it's used.
- I wasn't busy yesterday. I had already finished my work.
I wasn't busy in one past time, because previously I had finished my work.
- I ate a small lunch, because I'd already eaten a big breakfast.
I ate lunch at one past time, and I ate breakfast at a previous past time.
- When I arrived, the concert had just started.
I arrived in the past, and the concert started sometime before.

The Present Perfecrt connects the past and the present, for example:
- I haven't eaten today, so I want some food.

The Past Perfect connects two past times, for example:
- I hadn't eaten yesterday, so I wanted some food.

Similarly:
- We don't need an umbrella because the rain has stopped.
- We didn't need an umbrella, because the rain had stopped.

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