Hi
The Quickstart version is a normal joomla installation, with the all items included (components, modules, plugins) and database set with all the demo content. The process of the installation is quite as a normal joomla installation, except when you reach the part of setting name of website or admin name and password, this parts are already set by us also, so you can't change anything at this point.
After the installation is finish, naturally rename or erase "installation" directory and enter on administrator, using "admin" as username, "demo" as password.
Now that you have access to administrator board and have site installed as our demo, you can start making your own changes, including the name of the Site, changing admin password, etc.
If you want to see more, please follow this
video tutorial that uses Pulse Template as example, but the process is the same.
The Quickstart version is great from new live website or to used as guide to already live sites. This last one, with the quickstart installed on local server or on test live site.
Cheers