OpenIntegrations/docs/en/examples/Telegram/OpenForumTopic.txt

    Token = FunctionParameters["Telegram_Token"];
    Chat  = FunctionParameters["Telegram_ForumID"];
    Topic = FunctionParameters["Telegram_TopicID"];

    Result = OPI_Telegram.OpenForumThread(Token, Chat); // Opens main topic

    Result = OPI_Telegram.OpenForumThread(Token, Chat, Topic);