Complex sentence: Campino attended the Humboldt-Gymnasium in Düsseldorf, had to repeat twice and thus ended up in one class with Michael Breitkopf, co-leader of Die Toten Hosen.
Split into simpler sentences: Campino attended the Humboldt-Gymnasium in Düsseldorf. He ended up repeating twice and, due to this circumstance, he ended up in a class with Michael Breitkopf, co-founder of Die Toten Hosen.