//Create an instance of ConfigEditor Class:
//Make sure that your Win/Web Application has write and read privilege to selected config path 

//In Web
SimpleConfigEditor.ConfigEditor cfg = new SimpleConfigEditor.ConfigEditor(Server.MapPath("config.xml"));

//In Win App
SimpleConfigEditor.ConfigEditor cfg = new SimpleConfigEditor.ConfigEditor("config.xml");

//Set a Value:
cfg.Set("KEY", "VALUE");

//Get a Value:
cfg.Get("Key");

//Get a Value with Default Value, if Key Not Exist:
cfg.Get("KEY", "DefaultValue");

//Delete a Key from your Config File:
cfg.Delete("KEY");