So I'm on a tutorial mission I think is called Men of Arms, where there was an army coming from Pingyang and the tutorial encourages trying to manage that interaction before proceeding, so when I finished everything else before they came, I decided to do so. But now that I've already taken out their army and have nothing else to do I can't move on to the next mission.

I went to the Goals Tab to see if it was there, it says right-click to continue, I do and it takes me back to the current mission that I'm trying to leave.
There seems to be nowhere else to go to do so even though it said I should be able to, what am I missing?