Migrate a MyBB forum to Discourse

I’m converting users, post, topics etc from Mybb database!

I have followed this guide: Beginners Guide to Install Discourse on Ubuntu for Development

but http://localhost:3000/ or http://forum.omaggieconcorsi.com:3000/ don’t work

Anyway, the program is converting something, but I don’t know where I can then export the data.
Discourse I can’t see it with http://forum.omaggieconcorsi.com:3000/ or http://localhost:3000/ so how can I at least export the database with posts, users etc. from the old Mybb forum and then import it on new Discourse instance?

Thanks!