how we could recognise that we have to use simple past or past perfect in a sentence ?

Simple Past Tense describes actions or habits in the past and uncertain or likely future actions.

Example: "He always turned up late for the first class in the morning".

"I did not eat dinner last night".

The past perfect progressive puts emphasis on the course or duration of an action taking place before a certain time in the past.
Example: " I had been playing for an hour before he came."