daarna means “after that”. When it opens the clause, the verb comes before the subject (inversion).
Connective adverbs · Bijwoorden
Ik eet eerst. Daarna ga ik werken.
I eat first. After that I go to work.
We keken een film. Daarna gingen we slapen.
We watched a film. After that we went to sleep.
Drag scrambled words into the right Dutch order and master inversion and the verb-final rule.