Complete Example

Here is an minified example that uses all the funtions.

//+------------------------------------------------------------------+
//|                                                 Telegram4MQL.mq5 |
//|                                                   steven england |
//|           mailto:                                                |
//|         homepage: telegram4mql.steven-england.de                 |
//+------------------------------------------------------------------+
#property copyright "steven england"
#property link      "mailto:"
#property version   "1.00"
//--- input parameters
//input int      testparam;

#import "Telegram4Mql.dll"
   string TelegramSendTextAsync(string apiKey, string chatId, string chatText);
   string TelegramSendText(string apiKey, string chatId, string chatText);
   string TelegramSendScreenAsync(string apiKey, string chatId, string caption = "");
   string TelegramSendScreen(string apiKey, string chatId, string caption = "");
   string TelegramGetUpdates(string apiKey, string validUsers, bool confirmUpdates);
   string TelegramSendPhoto(string apiKey, string chatId, string filePath, string caption = "");
   string TelegramSendPhotoAsync(string apiKey, string chatId, string filePath, string caption = "");
   string TelegramSendDocument(string apiKey, string chatId, string filePath, string caption = "");
   string TelegramSendDocumentAsync(string apiKey, string chatId, string filePath, string caption = "");
#import

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnInit()
 {
 string apiKey = "112...:...J8";
 string chatId = "141...";
  int i = 1;
//---
   Print(TelegramSendTextAsync(apiKey, chatId, "test async text") + " async text");
   Print("async text sent");
   Sleep(2000);
   Print(TelegramSendScreenAsync(apiKey, chatId, "test async screen") + " async screen");
   Print("async screen sent");
   Sleep(2000);
   Print(TelegramSendPhotoAsync(apiKey, chatId, "F:\\Files\\GBPUSDH1.png", "test async photo") + " async photo");
   Print("async photo sent");
   Sleep(2000);
   Print(TelegramSendDocumentAsync(apiKey, chatId, "F:\\Files\\log.txt", "test async doc") + " async doc");
   Print("async doc sent");
   Sleep(2000);
   Print(TelegramSendText(apiKey, chatId, "test text") + " text");
   Print("text sent");
   Print(TelegramSendScreen(apiKey, chatId, "test screen") + " screen");
   Print("screen sent");
   Print(TelegramSendPhoto(apiKey, chatId, ""F:\\Files\\GBPUSDH1.png", "test photo") + " photo");
   Print("photo sent");
   Print(TelegramSendDocument(apiKey, chatId, ""F:\\Files\\log.txt", "test doc") + " doc");
   Print("doc sent");
   Print(TelegramGetUpdates(apiKey, chatId, false));
   Print(TelegramGetUpdates(apiKey, chatId, true));
   Print(TelegramGetUpdates(apiKey, chatId, true));
 }
//+------------------------------------------------------------------+

Then have a look at the Expert Advisors output.