The simple past in German is usually called Imperfekt, but also Präteritum (if you ever see that name, it's the same thing). It does not exactly correspond the simple past therefore we use here the name imperfect.

In the imperfect as well as in the present (see chapter 5 - conjugation of verbs in present tense) the type of the verb is important for its conjugation. First we'll have a look at the weak verbs and how they change.