So if you are trying to add a new template to an existing Joomla site that is using a Gantry 4 based template (i.e. myriad) then you would just download and install the "standalone" version of the "grunge" template. You could use the bundle package but there's no need as you already have Gantry 4 installed.
If you are trying to create a new website (i.e. different from the one you have using myriad) then you would actually use the "rocketlauncher" package on a brand new directory and database as it installs joomla, gantry, rt extensions, template and demo data all in one go.
Regards, Mark.
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