A very simple inline telegram bot as starting point (it tells you the time if you ask)

telegram-inline-bot.py

# pip3 install python-telegram-bot~=13.12

import datetime as dt
import os

from telegram import Bot, Update, CallbackQuery, InlineKeyboardMarkup, InlineKeyboardButton
from telegram.ext import Updater, CallbackQueryHandler, CallbackContext, MessageHandler, Filters

# inline keyboard sent with messages
main_menu = InlineKeyboardMarkup([[InlineKeyboardButton('time', callback_data='time'),
                                   InlineKeyboardButton('bar_cmd', callback_data='bar'),
                                   ]])

def handle_message(update: Update, context: CallbackContext):
    """ Will be called if bot gets a simple message - replies with inline buttons and greeting"""
    context.bot.send_message(chat_id=update.message.chat_id,
                             reply_markup=main_menu,
                             text="Hi, choose one of the options below")


def handle_callback(update: Update, context: CallbackContext):
    """ Handle callbacks from inline buttons """
    query: CallbackQuery = update.callback_query
    query.answer("Your add could be placed here...")
    key = query.data

    if key == "time":
        # answer query with current time, send same keyboard again
        query.edit_message_text(f"It's {dt.datetime.now().strftime('%Y/%m/%d %H:%M:%S')}", reply_markup=main_menu)


if __name__ == '__main__':

    API_Key = os.environ["API_KEY"]

    updater = Updater(API_Key, use_context=True)
    dispatcher = updater.dispatcher

    bot = Bot(token=API_Key)

    # add on message listener
    dispatcher.add_handler(MessageHandler(Filters.text & (~Filters.command), handle_message))

    # responsible for all inline commands
    dispatcher.add_handler(CallbackQueryHandler(handle_callback))

    # start bot
    updater.start_polling()
    updater.idle()