Simply add the include directory to your include paths, as this library is header-only it will be enough.
If you wish to compile the unit tests, installs XMake and enable unit tests with xmake config --tests=y before building with xmake and running with xmake run.
You can also package the library in a folder by using xmake install -o target_folder, on Unix-based system you can also install it system-wide by running sudo xmake install.