I've done everything I said I would. I trained the small army and attacked the easy targets. I still don't understand how many units I have actually trained and what they consist of. While I was training the troops, the icon showed this basic fighter - and yet, when I engaged the army, I saw I could also make use of knights or bowmen. I won the fights because they were easy ones, but many died. They were all automatic battles, except for the one time when I pressed the wrong button and I had to control the warriors myself. I had no idea what to do and failed to maneuver them properly.
On the one hand I should follow the objectives in the story. On the other hand, I should find a smart way to develop my city, and that seems to involve enjoying a large amount of resources. Before everything else, I am going to upgrade the buildings that can secure the stuff I need to do everything else, even though I will have to wait patiently for all the upgrades to be possible, and then done.
This is my wisdom now, after yesterday's foolish start.