Application configuration

Question

I am new to C#. I am developing a small windows application to train myself with. I faced an issue and can't figure out a good approach to it. My application needs a few configuration settings that shall be available for altering from users interface. I can build a form etc. but the problem is that I don't know how to keep custom settings. I tried application configuration file, defining a custom section and using IDictionary class instance for reading them. Well, I can read them but can't save them as they only get saved in System.Collections.IDictionary and don't get saved in the application config file. Is there any simple way to arrange custom configuration and read-write it? Can someone share a simple understandable example of it? I hope I explained it clear enough. Thank you all.