Build a New City
Here are the steps for building a new city:
1) First open the Nation Map by clicking on the Nation Map icon on the bottom bar.
(The world map is replaced by the nation map in this DLC)
It will open the Nation Map window, as shown below.

Then it will show that a new city development opportunity is currently available and you may acquire the exclusive rights to develop and run the new city for 30 years by donating a specific amount of money to the city’s treasury, as shown below.

Please note that if you have not formed a political party yet, you will have to form one first so that you will have somebody to fill the mayor’s role.
4) When you have successfully acquired the rights to develop a new city, the game will switch to show the new city, like the below screen.
