As I don't know every button on the ticket machine out of my mind, I'll translate the ones you can sell:
Scheme: Button on the ticket machine | Full German word | English translation
Fs Norm | Normaler Fahrschein | Normal ticket, changing the bus is allowed
Fs Erm | Ermäßigter Fahrschein / Schüler | Reduced ticket / students' ticket, changing is allowed
Kurzstrecke | Kurzstrecke | Short route
Kurzstr Erm | Kurzstrecke Ermäßigt / Schüler | Reduced short route ticket (for students)
Tagesk Nor | Tageskarte normal | normal day ticket
Hope I've helped