User Settings

I'm mean noob in c# and would like help in an application I'm running.

In this application I need the user settings to be Default , but I do not know a way to do this.

I'm developing in WebForms.

Can anyone help me?

A snippet of what I tried to do:

  private void PostTask(HttpClient client)
  {


        client.PostAsync("http://kronos/dotproject/index.php?m=tasks&a=view&task_id=1393",
            new FormUrlEncodedContent(new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("dosql", "do_updatetask"),
                new KeyValuePair<string, string>("task_log_task", (cmbTasks.SelectedItem as Task).IdTask.Substring(43)),
                new KeyValuePair<string, string>("task_log_creator", lblNome.Text),
                new KeyValuePair<string, string>("task_log_name", cmbTasks.Text),
                new KeyValuePair<string, string>("task_log_date", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")),
                new KeyValuePair<string, string>("task_log_hours", cmbHoras.Text),
                new KeyValuePair<string, string>("task_log_description", Descricao.Text),       
                new KeyValuePair<string, string>("email_assignees", "on"),
                new KeyValuePair<string, string>("email_task_contacts", "on"),   
                new KeyValuePair<string, string>("email_project_contacts", "on")    

            })).Wait();

        Properties.Settings.Default.Save();     
        /*var settings = Properties.Settings.Default;
        settings.SettingsKey = "value";
        settings.Save(); */
    }