In each examples (Tests directory) has the directory for each platform.
MacOSX - use Xcode open the *.xcodeproj then compile and run
iOS - use Xcode open the *.xcodeproj then compile and run
Android - use android studio open the _Android directory then compile and run it. You may need to config the local.properties to specific sdk and ndk directories.
Windows - use Visual Studio 2017 open the *.sln then compile and run. You need to use vspkg to install HarfBuzz first.
Emscripten - run make (you need to set path for emsdk tools first)
How using example?