make tgbot-cpp to listen on next message that user sends and handle it

[miannoodle01]

hello! i wish to know how should i wrote a code that for example, on writing "request", bot write this message and listen on the message the text the user will send. for example:
user: request.
bot: write your request.
user: i want the source code of the bot.
bot: your message will be delivered to admins.