"We went to school with him."
Translation:Chodili jsme s ním do školy.
Normally, with neutral stress, you begin a declarative sentence with the known thing and finish with the new information. So you could say "Chodili jsme do školy s tímto pánem.", but "s ním" sounds strange, because that points at someone who was mentioned before. You would have to be pointing at someone while saying "s ním" but still it does not sound right.
As I wrote, check the Tips and notes or any other resource about abstract and concrete verbs. Jet is used for a single concrete movement. Jezdit is for regular repeated movement.
Chodit do školy. is a specific Czech phrase. It means to go to school, to attend school. Jezdit do školy on the other hand is not about attending the school (with someone), it is about the actual way of commuting by driving or riding something (here together with someone).
My understanding of the English sentence is that it is about being schoolmates, about attending the school together, not about commuting together. However, I can't claim I understand all the nuances in English.
Thanks... I knew it was something about frequent/one-off events, but I couldn't remember which set of Notes I needed to find it.
To be fair, the English sentence could hold either meaning, which is why it's tougher to remember which one you need to satisfy Duolingo! It could mean 'we all attended the same school together for a long time', or it could also mean 'we accompanied him on the journey to school today' (for his first day, or for a meeting).
But that's a really helpful reminder of the difference when you're using Czech, so thank you.