Check out example codes for "c# make http request". It will help you in understanding the concepts better.

Code Example 1

private static readonly HttpClient client = new HttpClient();

var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");

Code Example 2

using System.Net.Http;
private static readonly HttpClient client = new HttpClient();
var values = new Dictionary<string, string>
{
    { "thing1", "hello" },
    { "thing2", "world" }
};
var content = new FormUrlEncodedContent(values);
var response = await client.PostAsync("http://www.example.com/recepticle.aspx", content);
var responseString = await response.Content.ReadAsStringAsync();

Learn ReactJs, React Native from akashmittal.com