The past simple tense is used to describe actions that were completed in the past. For regular verbs, the past simple form is created by adding "-ed" to the base form of the verb. Irregular verbs have varying past simple forms that must be memorized. Examples of common regular verbs like "talked" and irregular verbs like "ate" are provided. A practice exercise asks the reader to fill in the blanks with the correct past simple form of verbs like "tidy" and "phone."