In Telegram, open BotFather, send /mybots, pick your bot and choose API Token. Copy the token.
In TGBots, open My bots, choose Connect a bot and paste the token.
We store the token encrypted. It is never shown again, logged or sent back to your browser.
To remove it, open the bot's Settings and choose Disconnect. You can also revoke the token in BotFather at any time.