I'm not a native speaker, so it's difficult to explain accurately. But at first you should learn past tense auxillary verb DID. Also you should know that verbs in past tense change, you need to add -ed to the end of the word, if it's not an irregular verb. Learn irregular verbs and use them in past tenses. So if you ask a question about past use it. If you want to use a verb TO BE, you have to use its past form WAS or WERE