Hello. Here is a useful slide to know different verb tenses including past tense. There are also formats with sample sentences.
simple past is used when it's a short complete situation that happened in the past.
past continuous is for an ongoing situation that was happening in the past it's not completed, pretty much used to tell a story.
Past perfect is for a situation that started in the past and somehow is related to another situation/ event in the past.
past perfect continuous is an ongoing situation in the past that's related to an event in the past.
Now some examples:
I watched a lot of prograrms yesterday ( situation/event already fnished)
I was watching t.v. yesterday ( situation/event finished, but is used to tell a story)
I had watched a lot of programs but i never tried to imitate them. ( this is related to another situation)
I had been watching a lot of programs about medicine since i was a kid ( setting a background for a story).
I hope this can help you a little :)