Bonjour
First of all, ther"s a mistake in the passé composé :
the passé composé of "être" is the auxiliary "avoir" in the présent tense + the past participle of "être" => été
j'ai été
tu as été
il/elle/on a été
nous avons été
vous avez été
ils/elles ont été.
They are both past tenses.
The "imparfait" is a simple tense that you use to describe things in the past, with no specific indications "when" "where", that were happening on a regular basis, or non specific number of time...
The "passé composé" is a compound tense that you use for completed actions, when the action happen a specific number of time, when an action interrupts one which was in the "imparfait".
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hope this helps☺☺☺