To understand the concept of the Linux file system, you need to the following:
The Hierarchical Structure of the File System
FHS (Filesystem Hierarchy Standard)
Root Directory /
Essential Binaries for Use by All Users (/bin)
Boot Directory (/boot)
Other Partitions (/data)
Device Files
Configuration Files (/etc)
User Directories (/home)
Libraries (/lib)
Mountpoints for Removable Media (/media/*)
Application Directory (/opt)
Home Directory of the Administrator (/root)
System Binaries (/sbin)
Data Directories for Services (/srv)
Subdomain AppArmor (/subdomain)
Temporary Area (/tmp)
The Hierarchy below /usr
Variable Files (/var)
Windows Partitions (/windows)
Process Files (/proc)
System Information Directory (/sys)
Mountpoint for Temporarily Mounted File Systems (/mnt)
Directories for Mounting Other File Systems