Every folder or file is contained within C:\
Your Operating systems files are contained here.
Additional Programs reside here.
Files you create are stored here.
  If we create a file called mylife.doc and place it in C:\My Documents then the path to this file will be:
C:\My Documents\mylife.doc
  If we intend to create many documents to be stored into C:\My Documents it would be
advisable to categorize them. One could create folders such as "letters" "mybook" "work". Then files pertaining to these folder names could be stored inside. Examples below:
C:\My Documents\letters\dearjohn.doc
C:\My Documents\mybook\chapter1\chapter1.doc
C:\My Documents\work\proposal.doc
Note: this discussion pertained to C:\. It is possible to "partition" a hard drive into "slices". This could result in one drive containing what appears to be many drives. One could create C:\, D:\, and E:\ on one drive.