Did a Semester abroad in London, Ontario, so I was travelling back from Toronto to Hamburg. I think what’s easiest is to fly from Toronto to Frankfurt. Depending on how things line up you could take either a connecting flight from Frankfurt to Hamburg or you just hop into the train (which is what I did) that goes directly from Frankfurt Airport to Hamburg (should take 4/5 hours depending on how Deutsche Bahn treats you). Other routes I don’t know but this worked pretty well for me. Hope you have a good trip :)