Modal verbs are commonly used in their preterite/simple past form in both written and spoken German. Although the present perfect forms do exist, they are not really used. Notice that the umlauts are dropped when forming the past tense of these verbs.
N.B. The simple past forms of the modal verbs are the basis for the formation of the general subjunctive (modals with an umlaut in their infinitive forms (müssen, dürfen, können, mögen) add them to the simple past), which is covered later in this course.