Use the Past Simple to talk about completed or finished actions in the past.
I asked her to call me back.
The director didn’t get your memo this morning.
Where did you go for your last holiday?
Agatha read a 400 page book in just two days.
Eric lived in London for two years.
Use the Past Continuous to talk about actions in progress in the past.
Anna was jogging in the park on Saturday.
I’m sorry, I wasn’t paying attention. Could you repeat please?
What were you doing last weekend?
Agatha was reading all weekend.
Sonia was staying with some friends until she could find a flat.
The past simple is often used together with the past continuous to show that an action happened while another action was in progress. We use the past continuous to describe the action that was in progress while we use the past simple to describe the action that happened or interrupted the other action.
Wendy called while we were having dinner.
(We were having dinner is the action in progress, while Wendy called is the action that happened or interrupted the other action)
Derek was shopping when he saw a robbery take place.
(Derek was shopping is the action in progress, while he saw a robbery is the action that happened or interrupted the other action)