Here are some examples:
* I was at the store yesterday.
* She was at the park.
* He was at the movies.
* They were at the store yesterday.
* We were at the park.
* You were at the movies.
Was is also used to talk about things that happened in the past that are still true today.
* I was born in 1990.
* She was a teacher.
* He was a doctor.
Were is also used to talk about things that happened in the past that are no longer true today.
* They were friends.
* We were enemies.
* You were strangers.