Past simpleSomething happened in the past and is now finished.
Past time references:
yesterday, last week, in 2015, in the 18th century, 2 years ago, etc.
Present perfect1) Something began in the past and is still going on now.
2) Something happened in the past and is still noticeable now.
3) Talking about experiences you've had so far.
JUF EN SYSAH:
just, until, for / ever, never / since, yet, so far, already, how long