We use to talk about actions and states which we see as
completed in the past.

Is used when we want to look back from the present to the past.
We can use it to look back on the recent past.
When we look back on the recent past, we often use the words 'just' 'already' or the word
'yet' (in negatives and questions only).
It can also be used to look back on the more distant past.
When we look back on the more distant past, we often use the words 'ever' (in
questions) and 'never'.