Difference between Simle Past and Present Perfect

Simple Past:
I read the article yesterday.
--specific time, task completed.

Examples:
I worked hard "yesterday/last week/last month"

Questioning:
When did you move to USA? --- exact time


Present Perfect:
I have read the article.
--no specific time, task completed sometime in past.

Examples:
I have worked hard this "week/semester"
I have worked hard since "6 am/January"

Questioning:
How long have you been in USA? --- duration of time