As long as you're using one of the newer shapers (everything new enough to still be relevant), you can just copy the wp-content folder to your server, then activate the "Sample Data Injector" plugin on the sub-site where you want the shaper installed.
I highly recommend deleting the plugin after it installs the sample data, as it erases all existing data before installing the sample content.
I definitely recommend using a test server as a reference, just to make sure you have access to the demo content during the full process of setting up the real site.
You can also find written instructions on how to install a shaper on the
Wordpress FAQ; the "auto-installer" method is closest to what you would do for a multisite.