PAST TENSE

On this page we can see in an easy way the explanation about the past tense
like they present you several exercises to put what you learned in practice
  https://www.curso-ingles.com/aprender/cursos/nivel-intermedio/verb-tenses-past/past-simple


how to use was, were?


                *I                                                *You   
   WAS     * He                             WERE   *They
                * She                                          *We
                *It
             

positive way 
Example:     • I was at home (Yo estaba en casa)
                   • You were at home (Ellos estaban en casa)

negative way 

Each initial name must be added a "not" later to create the negative tone. When is says "I was not" in can be contracted saying " i wasn´t"

Example:    • I was not at school (Yo no estaba en la escuela)

                     I wasn’t at school

                  • You were not at school (Tú no estabas en la escuela)
                    You weren’t at school

as a question 

We start with the "was" continue with the I, He, She or It and conclude with the complement of te question.
The same with the were putting of the second You, We and They.

Example:   • Was he friendly? (¿Él era amigable?)
                 • Were they friendly? (¿Ellos eran amigables?)

(this is in a positive way)

(It is important to add that there is an interrogative form in a negative tone.) 

What we should do is simply change to "was not" and "wasn´t"

DID

The verb DID is used to put the questions or answers in the past tense. It is placed in front of the pronoun (I, YOU, SHE, HE, IT, YOU, WE, THEY), and is used as an auxiliary in the questions. Example: Did you eat sandwich? Yes, I did ---- No, I did not   You can answer the questions in two ways: NEGATIVES: Did not POSITIVES: Did Also in a long and short form. When the question has the verb in the present and it is not addressed to the third person (SHE, HE, IT). When it is for the third person a verb in the past will be used, but when you are going to respond in a long way, you have to pass that verb in past to present, because every verb in the DID must be in present tense, but it will continue to be passed thanks to the DID. And if you use the third person in a question, you have to put one (S) or (ES) to the verb of the question. EXAMPLE: Did she dances in the party? DID means: power or you can