There are many irregular verbs in English, which means they don’t follow the main rule of adding –ed to the verb.
Here you are some links to different exercises for practicing the past simple of irregular verbs.
Remember, the structures of this kind of verbs are:
Affirmative: Subject + irregular verb + complements.
Negative: Subject + did not + main verb (infinitive) + complements.
Interrogative: Did + subject + main verb (infinitive) + complements + ?
Enjoy your holidays. Happy Easter/Holy Week. Regards, Christopher.