Adding Logger to your project is very simple. Start by downloading the file, you can do this by going to c++/src/Logger.hpp and clicking the Download Raw File button in the top right. Save it to wherever you want it in your project.
This is also very simple. At the top, with your preprocessor directives, add this line:
...
#include "/path/to/Logger.hpp"
...
Notice how I included the path to the Logger file as well. Your path will be wherever you saved the file to.