To explain to your Camke that you have to build KapUI, you have to edit packages.cmake file. This file is located at Packages directory. All you need to do is to add this line in file :
include_directories(Packages/KapUI)
Build your project
To build your project with KapUI, you just have to execute build.sh. This shell file gonna build your game with all submodules that you need.
Use compressed file
With github you can also download the code source of KapUI. This method cannot alow you to update the version of KapUI.
When you downloaded the version that you want, you just have to add all files in a directory call KapUI in Packages directory.
Cmake
To explain to your Camke that you have to build KapUI, you have to edit packages.cmake file. This file is located at Packages directory. All you need to do is to add this line in file :
Build your project
To build your project with KapUI, you just have to execute build.sh. This shell file gonna build your game with all submodules that you need.