Linking verbs show existence, not action, and they link the subject to another name for the subject.
Here are two past tense linking verbs: was and were
Use was with subjects that are singular – one person.
I was a good student.
Mom was a nurse.
My grandmother was a teacher.
My neighbor was a big help.
Use were with subjects that are plural – more than one person.
The boys were baseball players.
My uncles were soldiers.
The three girls were cheerleaders.
We were troublemakers.
Use the linking verbs was and were for past tense when you want to show existence.