Sorry, not sure what the intention was with that other message.
I noticed some issues with the multi site plugin so I just uploaded a new version of Typesetter (ver 5.0.3) with fixes.
To use the multi site plugin, you'll need to first install the multi site plugin:
Once installed, the main admin page for the Multi Site Plugin will be at http://your-typesetter-installation/index.php/Admin_Site_Setup
From there, you can select the folder you want to create additional installations in.