REVISIÓN DE TIEMPOS VERBALES PERFECTOS.

The present perfect is formed from the present tense of the verb have and the past participle of a verb.

for something that started in the past and continues in the present:

They've been married for nearly fifty years.

I've seen that film before.

My last birthday was the worst day I have ever had.

https://learnenglish.britishcouncil.org/english-grammar-reference/present-perfect

We use have/has been when someone has gone to a place and returned:

A: Where have you been?

B: I've just been out to the supermarket.

We normally use the present perfect continuous to emphasise that something is still continuing in the present:

It's been raining for hours.

I had finished the work.

for something that started in the past and continued up to a given time in the past:

When George died, he and Anne had been married for nearly fifty years.

I was sorry when the factory closed. I had worked there for ten years. 

I had been working there for a year.

She didn't want to move. She had been living in Liverpool all her life.

He was a wonderful guitarist. He had been playing ever since he was a teenager.

I had been watching that programme every week since it started, but I missed the last episode. 

https://learnenglish.britishcouncil.org/english-grammar-reference/past-perfect

The guests are coming at 8 p.m. I'll have finished cooking by then.

On 9 October we'll have been married for 50 years.

Will you have gone to bed when I get back?

I won't have written all the reports by next week.

By the time we arrive, the kids will have gone to bed.

I'll have finished in an hour and then we can watch a film.

https://learnenglish.britishcouncil.org/grammar/intermediate-to-upper-intermediate/future-continuous-and-future-perfect