1 - Did you add your user ID to your bot chatbot-Telegram-node configuration?
Secondly, check your bot settings by using the BotFather -bot.
2 - Answered it all ready on [HowTo] Setting up a Telegram Bot for all your Home Automation messages - #8 by Domoticon
3 - It is stored in msg.payload.content. You can use a change-node to move it or a function node with coding.
For debugging please use a debug-node with ‘complete message’ enabled. You can see the complete content of the received message and check debug window on the right site. That’s how I learned the basics of NR. (with a lot of trial and error 
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