Setting up new iPhone as new to update software and then need to restore backup from old iPhone

My new iPhone would not let me set it up using the data from the iTunes back-up of my old iPhone, because the new iPhone was not running the latest software. (Why is that, you might ask, as it had just been delivered today? Good question, but for another day...) So, I did that -- set it up as a new iPhone and then updated the software to the current iOS. That worked. But now how do I transfer the data from my old iPhone using the iTunes backup?? I don't see an obvious choice in iTunes or the new iPhone...