You should reply to the email you’ve received with this exact text, as it says:
@discobot start advanced tutorial
From what I know, discobot is a kind of an extension (plugin) for a Discourse based forum (like this forum). It’s a robot … or better known as a bot. It’s a funny, automatic bot that can great new users on the forums, show them certain tutorials, help them with basic things, etc. It’s a small piece of software, an extension, instructed do do basic things based on a rules engine.
On a forum (not only on this one, but on others too), users can do things based on their level of trust. Your level of trust was increased automatically based on your activity on the forum, so to know what you can do from now on, just reply to that email and you’ll receive details about what and how you can contribute in these forums from now on