"I have fourteen tests today."
Translation:Ik heb vandaag veertien toetsen.
I think that adverbs referring to Time/Manner/Place need to come before the Direct Object/right after the finite (conjugated) verb.
Unless you put such adverbs at beginning, as in Vandaag heb ik veertien toetsen. (In that case, you have subject-verb inversion)
But I'm a learner as well, so I could be wrong!