A Telegram bot is a free account type. Free forever. Takes 60 seconds.
Open Telegram on your phone or desktop.
If you do not have it: telegram.org/download.
In the search bar at the top, type @BotFather.
Tap the one with the blue tick.
Press Start. You will see a menu of commands.
Send the message: /newbot
BotFather asks for a display name. Type any name you like.
e.g. "My Brain". This is what shows above the chat.
BotFather asks for a username. Must end in "bot".
e.g. "my_brain_bot". If taken, try another.
BotFather replies with a long string starting with numbers and a colon.
→ paste into TELEGRAM_BOT_TOKEN
Copy that string. Paste into the wizard field labelled "Telegram bot token".