For example, under the Restore heading, it explains that "You can use shadow copies to restore previous versions of files that have been accidentally modified or deleted." That sounds great...I think. It begs the question "what is a shadow copy?"
Thankfully, Microsoft already realized the question was begged. Immediately following the explanation sentence, you will find the question "what are shadow copies?" which links to the FAQ to give you an explanation.
This type of assistance and explanation is always a click away throughout the Backup and Restore Center.