How do I use the present tense in German?

First: Start with a comparison with English (different tenses for the present in English vs. A single one in German)

Second: Evoke the difference between strong and weak verbs in German, do a parallel with English 

Third: Give a first example with a weak verb --> "kochen" (= to cook)

ich koche , du kochst, er kocht, wir kochen, ihr kocht, sie/Sie kochen 

Fourth: after having explained the endings for the weak form, evoke some variations (if verb stem ends in t, d, m, n / ex: arbeiten "to work") (if verb stem ends in s, z or ß / ex: heißen "to be called")