Home>>Domains>>(select domain of master site)>> Domain Aliases – put in the name of the new joomla site
Log into the Joomla Master Site Admin >> Components >> Multi Sites >> Manage Sites >> New
Fill out Site Details property sheet and Save
Goto Joomla install page via the alias created for the master Domain
Follow prompts until database page. Enter info for Master database. Important! click the Advanced button and change from the default prefix jom_ to another name.