Here’s when we use it:
1 Finished events in the past with no connection to the present:
Leonardo painted the Mona Lisa.
The Vikings invaded Britain.
2 With a finished time word (yesterday, last week, at 2 o’clock, in 2003):
I went to the cinema yesterday.
We visited Japan in 2007.
3 For stories / lists of events:
He went to a café, sat down and lit a cigarette.
Yesterday I went to the library, met a friend for lunch, and played tennis.
4 Details of news:
I’ve hurt my leg. I fell off a ladder when I was painting my bedroom.
I’ve been on holiday. I went to Spain and Portugal.
5 As part of the second conditional:
If I won the lottery, I would buy a house in Chelsea.
If she knew his number, she would call him.