1. THE PAST SIMPLE TENSE The past simple tense is used for:
actions or events in the past:
I visited Egypt last year.
actions or events which happened one after another:
I saw the Pyramids, then I went round the Cairo Museum and later I went to a traditional restaurant.
things which happened for a long time in the past:
She lived in Zurich for ten years from 1992 to 2002.

2. THE PAST CONTINUOUS TENSE
The past continuous tense is used for:
an activity which started before and continued until an event in the past:
He was driving to work when his car broke down.
an activity which started before and continued after an event in the past:
I was watching television when the news was announced. (and I continued to watch television afterwards)
Remember: state verbs are not normally used in the continuous!

3. USED TO Used to is used for:
situations or states in the past which are not true now:
He used to be in the army, but he is a teacher now.
repeated activities or habits in the past which do not happen now:
She used to run in the London Marathon every year until she injured her leg.
Note:
used to is a verb which is only used in the past:
She used to run in the Marathon.
Did you use to run in the Marathon?
I didn’t use to run in the Marathon.
to talk about habits in the present, use the present simple tense with an adverb like usually, every day, etc.:
I usually drink tea with my lunch.
He catches the same train every day.

4. THE PAST PERFECT TENSE Is used:
to indicate that we are talking about something which happened before something which is described in the past simple:
When he got to the station, his train had already left.
typically with time expressions like: when, as soon as, after, before, etc.:
She started driving before he had fastened his seatbelt.
often with these adverbs - already, just, never:
He had never eaten steak and kidney pie until he came to England.

5. THE PAST PERFECT CONTINUOUS TENSE
Is used:
to indicate that we are talking about something which happened before something which is described in the present simple tense, but it:
- focuses on the length of time:
Mandy needed a walk because she had been sitting down all day.
- says how long something happened up to a point in the past:
It was two months before any of the teachers noticed that Paula hadn’t been coming to school.
He had been playing for Arsenal for only two games when he scored his first goal.