hierdoor means “because of this”. When it opens the clause, the verb comes before the subject (inversion).
Connective adverbs · Bijwoorden
De les werd verzet. Hierdoor had ik meer tijd.
The class was moved. Because of this I had more time.
Er was file. Hierdoor kwam de bus later.
There was a traffic jam. Because of this the bus came later.
Drag scrambled words into the right Dutch order and master inversion and the verb-final rule.