Present Perfect and Simple Past

Simple Past 

Use the past simple to talk about activities or routines which take place at a specified time in the past. Notice that all subjects take the same conjugation of the verb. 

Regular verbs end in '-ed'.

visit - visited

enjoy - enjoyed

Irregular verbs have various forms and each verb needs to be learned.

see - saw

think - thought

The past simple is used to express a finished past action which occurs at a specific moment in the past.

Examples

She visited Iran last month.

They didn't go to Tom's party last weekend.

Where did you go on vacation last summer?

The simple past expresses an action in the past taking place once, never, several times. It can also be used for actions taking place one after another or in the middle of another action.

1) action finished in the past (single or repeated)

I visited Berlin last week.
Andrew watched TV yesterday

2) series of completed actions in the past

First I got up, then I had breakfast.

3) together with the Past Progressive/Continuous - The Simple Past interrupted an action which was in progress in the past.

They were playing cards when the telephone rang.
1st action: Past Progressive were playing
2nd action: Simple Past rang