How does one make a Telegram MTProto protocol api call?

For instance to call/wrap the auth.sentCode method (link below):

https://core.telegram.org/method/auth.sendCode

I have tried:

var url = "https://149.154.167.40";  
var data = "(auth.sendCode \"PHONE_CODE+NO\" 0 APP_ID \"SECRET_HASH\" \"en\")";  
using (var wc = new WebClient())  
{  
var result = wc.UploadData(url, GetBytes(data));  
}

I get this exception (and inner exception)

The underlying connection was closed: An unexpected error occurred on a send. (Authentication failed because the remote party has closed the transport stream.)

Solution

You an get started with this SO post

You would need to understand how to generate an AuthKey first.

The Telegram-API documentation is not very well written, but if you keep studying it... you eventually get the hand of it.

Working through generating the AuthKey would help you build up a pattern and functions that you can then use to tackle the rest of the API

Cheers.