Sam, don't use the "Add Library.." part in the guide. If you are just trying to compile with the .jar, just add the jar to the project
I pushed a sample project to github for using OkHTTP. See here:
1) Make sure you have added the OKHTTP jar in the libs folder inside your project.
2) Make sure to add the jar in your application's Java build settings.
3) Make sure to add the "uses internet" permission in your android app (see the AndroidManifest.xml file in the project)
4) Make sure you use the square library in an AsyncTask or a thread (my example uses the AsyncTask). Since Android 4.0, Android will not allow you to make a network call to get data on the UI thread. Otherwise the UI thread (which is responsible for responding to user events like updating the interface when the user clicks around or scrolls, etc) will get blocked and your app will appear frozen
If you want to import the OkHTTPTest project, just download it from Github and in eclipse you can do File > Import project. Let me know how that goes.