Top wat battle game requires frequent upgrades to your buildings or soldiers.
But there is no separate button to operate the upgrade.
Let’s introduce how to upgrade the building.
First, two recommendations of the same level are needed
Drag and drop together manually.
Will synthesize more advanced buildings.
In addition, the building needs to click on the build interface in the lower left corner of the main interface.
The level of the built building can also be researched in the research center~