Preconfigured distributions or simpler distributions are a kind of TYPO3 extensions which allow you to get started easier.
In the beginning such packages weren't included in TYPO3, so many people installed the CMS but were then left alone don't knowing how to go on.
"Oops, an error occurred!"
"No pages are found on the rootlevel!"
You either download them while installing TYPO3 or can implement them within the module "Extensions".