@Koishi @isi to explain the linux directory structure in a nutshell:
/bin - system binaries
/boot - the bootloader
/dev - device files representing the devices attached to the system
/etc - configuration files
/home - home directories of users
/lib - shared libraries required for boot
/media - the typical place where removable media are mounted
/mnt - temporary mount point regular file systems
/opt - optional files, such as vendor applications
/root - home directory for the root user
/tmp - temporary files
/usr - read-only shared files including binaries, libraries and documentation
/var - variable data, like logs, databases, webserver files, etc.