Past tenses

Past simple: worked, stopped, went, had, ...
Use the past simple for finished past actions.
They got married last year.

Past continuous: was/were + verb + ing
Use the past continuous to describe an action in progress at a specific time in the past.
What were you doing at six o'clock last night?

Past perfect: had + past participle
Use the past perfect when you are talking about the past and you want to talk about an earlier past action.
I felt nervous because I hadn't flown before.

Using narrative tenses together
When Paul arrived, they had dinner. (first Paul arrived, then they had dinner)
When Paul arrived, they were having dinner. (when Paul arrived they were in the middle of dinner)
When Paul arrived, they had had dinner. (they had dinner before Paul arrived)