Adding Logger to your project is very simple. Start by downloading the file, you can do this by going to c#/src/Logger.cs 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. Modify your compilation command to include /path/to/Logger.cs. Here's an example command:
mcs -out:dist/LoggerTester.exe src/Main.cs
And here's the modified version:
mcs -out:dist/LoggerTester.exe src/Main.cs src/Logger.cs
Notice how I included the path to the Logger file as well. Your path will be wherever you saved the file to.