Watch the video.
It will help you understand the difference between Present Perfect and Past Simple.
Present Perfect is similar to the past, but with no specific time:

And it is centered in the experience, not time:

Other examples:
PRESENT PERFECT

The PRESENT PERFECT is often used with the following time expressions:
How long...?
...for...
...since...
...just...
...lately
...recently
...ever...
...already...
...never...
...yet...
PAST SIMPLE

The PAST SIMPLE is often used with the following time expressions:
... ago
... yesterday
...last week / month / year
...
EXERCISES ON USE: Past Simple or Present perfect?: