How to add AFNetworking to XCode app
It sounds like you got the first part down, which is downloading it from the GitHub page.
When I follow this tutorial, it shows how they imported AFNetworking into their own sample project (that is, you'll see a "AFNetworking" group in the list of files and folders along the left side of your Xcode window).
Once AFNetworking is building along with the rest of your code in your project, you should be able to call into the various AFNetworking API's from your code. You'll need to make certain to add in the appropriate "#import "AFNetworking.h"" lines into your source code files from which you'll be calling AFNetworking.
Use pods, than you wont have to upload AFNetworking to your github project, and there is no worry about wrong linkers etc.
Use pods: install pods
Instalation AFNetworkign with pods: install AFNetworking