dan means “then”. When it opens the clause, the verb comes before the subject (inversion).
Connective adverbs · Bijwoorden
Als het kan, dan kom ik.
If it's possible, then I'll come.
Doe eerst dit, dan doen we dat.
Do this first, then we'll do that.
Drag scrambled words into the right Dutch order and master inversion and the verb-final rule.