E-primbon

The perfect tenses express the idea that something happened (or never happened) before now, at an unspecific time in the past. The exact time it happened is not important
=>Formula:
S+have+V3+object/adjective/advent

Examples:
They have moved into new apartment
Have you ever visited Pulpis city?
I have already seen that movie
I have never seen now

Note:
If there is a specific mentron of the time, the simple past is used.
Ex: I saw that movie last night

The present perfect also expresses (when used with for a since) a situation that began in the past & continues the present
Ex: I have been here since seven o’clock