In this section we are going to use `cd` command to navigate through directories. cd is internal built tool in linux which is very useful to navigate throuh directories. Before navigating through directories ,you must understand about path.
cd [address or path]
Path is address of directories or files.
1.    ` . ` this represents the current directory.
3.     Absolute address is address of directory or file from the root of the file system. Ex : Documents directory in home absolute address is /home/userHome/Documents/ . First `/` is root and `home` then `userHome` is under /home directory then Documents is under `userHome` directory. It's a hierarchy.
4.     Relative address is address related to the current directory you are right now. Ex : if you are in /home directory of your user then `.` is current directory. If you cd with `.` then you remain in same directory. If cd ./Documents then it goes in Documents as `.` is current directory and Documents is under current Directory. Try to play with address for better understanding.