First find “Townhall” on the castle interface

(Here take Human as example)

Click “Townhall” and you will see a list of buildings.

 

If you look at it carefully, you will find that some icons on the right side of the buildings are dark and some are bright. These bright icons indicate that these buildings meet the requirements for construction.

 

 

You can click  button on the right to start construction.

 

And then click “Enter Townhall” button below the building list and you can see buildings currently under construction.

 

Upgrade buildings. Click any building on the Castle Interface

Just take embassy as example

 

Click it and you can see the embassy interface

 

Click “Upgrade” button and you can upgrade the selected building

 

 

You can view upgrade information in the townhall.