Mobile Partie Supérieure Gauche
This number tells you how much free population you have. If you tap here, it will open a small window telling you what your total population is, and how much free population you have available for you to use.
Next is the smiley face which indicates the current happiness of your city - you want to try and keep this gold as much as possible, as this means your towns people are enthusiastic which gives you a 120% boost to productivity. All coin and supplies buildings will produce more, as well as receiving a boost in points given when you win fights. Again, tap this icon for a more detailed overview.
Here you can see your current global ranking. At the moment, tapping this icon doesn't open an additional overview, but there are plans to give you a much more detailed overview in future versions of the app