Flowchart
Past Simple vs Present Perfect
Flowchart content
Do you say WHEN it happened?
Use Past Simple: I joined this company last year.
Past Simple or Present Perfect?
YES
Use Present Perfect: I've just joined this company.
NO
Is this a RECENT event?
No, it is a finished action in the past, and it happened in a finished period of time.
Yes, it happened this week/month/year, and this period of time isn't over yet
Use Past Simple: I started this project back in 2015.
Use Present Perfect: This month, I've already sold 20 cars.
Did you do it ONCE?
YES
Use Past Simple: I heard about this company.
NO
Use Present Perfect: I've heard about this company five times!