step

• create bot and get token
• create deno project and create file .env or rename .env.example to .env
• set token for .env file with key BOT_TOKEN with value "telegram token"
• library:

    import { Bot } from "https://deno.land/x/telegram@0.1.2/bot.ts";
    import "https://deno.land/x/dotenv/load.ts";
  
    // update to    
    import { Bot, Context } from "https://deno.land/x/telegram@master/mod.ts";
    import "https://deno.land/x/dotenv/load.ts";

• url random image cat: http://placekitten.com/200/200
• url random image : https://picsum.photos/200/300/?random