The workflow is the same for version 3, there are very few differences. Otherwise here’s the main support page:
http://support.nextlimit.com/display/mxdocsv3/Maxwell+Render+V3+Documentation/
This is the page with all the new version 3 features, and direct links to their info pages:
http://support.nextlimit.com/display/mxdocsv3/3.0+release+notes