If you open your Buildings menu, you can see the Expansions tab at the very right side.
Clicking on that tab opens the Expansions selection:
You can see that the Premium Expansion is available for purchase with diamonds. In this picture is currently no Province Expansion available. To get a Province Expansion available, you need to complete provinces. How many provinces are needed is shown when you hover with your mouse cursor over the Province Expansion section:
Now enter the World Map and select the Province Overview and you might see such a list of Scoutable Provinces:
Select the Incomplete Provinces and you might see such a list of Incompleted Provinces:
Here you can now select a Province to complete in order to reach the following message window:
Now go back to your city and open the Buildings Menu again. Select the Expansions tab and you should see now a window like this:
When you click on the green bar with 'Place', this window closes and you get prompted to your city which will look similar to this one:
The sections that are fenced in are available for putting down your expansion:
Here is the top corner Expansion selected. Press 'Done' and your new Expansion is available for moving in.
If you have finished the Research for an Expansion, you need to go to your Buildings Menu, Expanion tab and there you can place that Expansion. But this Expansion is not free!
Here you can see how many coins or how many diamonds you will have to pay in order to place the Research Expansion. So if you are not able to place your researched Expansion, have a close look into this Buildings tab.
Please note that this thread was writting on the basis of the browser version of the game. The mobile version can be different.
Clicking on that tab opens the Expansions selection:
You can see that the Premium Expansion is available for purchase with diamonds. In this picture is currently no Province Expansion available. To get a Province Expansion available, you need to complete provinces. How many provinces are needed is shown when you hover with your mouse cursor over the Province Expansion section:
Now enter the World Map and select the Province Overview and you might see such a list of Scoutable Provinces:
Select the Incomplete Provinces and you might see such a list of Incompleted Provinces:
Here you can now select a Province to complete in order to reach the following message window:
Now go back to your city and open the Buildings Menu again. Select the Expansions tab and you should see now a window like this:
When you click on the green bar with 'Place', this window closes and you get prompted to your city which will look similar to this one:
The sections that are fenced in are available for putting down your expansion:
If you have finished the Research for an Expansion, you need to go to your Buildings Menu, Expanion tab and there you can place that Expansion. But this Expansion is not free!
Here you can see how many coins or how many diamonds you will have to pay in order to place the Research Expansion. So if you are not able to place your researched Expansion, have a close look into this Buildings tab.
Please note that this thread was writting on the basis of the browser version of the game. The mobile version can be different.