Hi,
first you have to issue "cli" + ENTER and then "configure" + ENTER. The first is only necessary as root and the latter activates the configuration mode. And yes, "commit" + ENTER applies your changes.
The initial setup wizard (EZSetup) asks you on some point if you like inbound or outbound management. If you ask inbound, it configures vlan.0, if you say outbound, it configured the me0 interface.
me0 is the name of the management interface. I don't know it for sure, but I would suspect it just means Management Ethernet (port).
I think it would be the best if you review the excellent learning resources for the switching platform. This should give you a fast introduction on how the Juniper switches work and how you should configure it.
Just sign up (for free) at the Juniper fast track website (https://learningportal.juniper.net/juniper/user_fasttrack_home.aspx). There you can review a short video training (see the link to Take the Juncos as a Switching Language eLearning course) and download a training PDF under the Review Study Resources link.
If you have questions, just ask.
Regards,
Dominik