Hello G., welcome to Using English!
The Greek aorist is closer to the English simple past tense than to the English present perfect.
On the whole, the English simple past expresses an event that is complete:
1. I bought a pair of trousers yesterday.
2. He died in 1862.
The present perfect, on the other hand, usually expresses a past event with a present connection:
3. He has gone to visit his sister.
i.e. he went recently to visit his sister, and is still there.
4. How long have you been working at the university bookshop?
i.e. he started working at the university bookshop in the past and is still working there.
5. How long did you work at the university bookshop?
i.e. he no longer works at the bookshop.
Let me know if it's still unclear!
All the best,
- For Teachers