Our last blog looked at irregular verbs in the present tense. We want to dedicate this blog to irregular verbs in the simple past. Verbs are sometimes categorised into regular, irregular and mixed verbs. Mixed verbs are irregular verbs but do not change their stem in the present tense. Mixed and irregular verbs constantly change their stem in the simple past. Your verb list indicates this with the 3rd person singular in the simple past, sometimes called imperfect or preterite. With irregular verbs in the simple past, unlike in the present tense, the 1st person singular and the 3rd person singular is identical. The 2nd person singular ends in -st, as in the present tense, the plural endings are -en, -t, and -en.
Now, a little about the usage of the simple past vs the perfect tense. The simple past is more often used in written German, whereas the perfect dominates in spoken German. There are geographical differences, though: the simple past is still quite often used in spoken German in the northern regions of Germany, and the southern regions prefer the perfect in spoken German. If anything you are talking about has happened in the past and is still relevant, then you better use the perfect for pointing this out.