It is sometime necessary to have some windows for working. In case you have linux/unix server it will be easier to use client program such as putty to log in and open another putty if you want to open new windows. But if you are working in front of your computer server, opening two or more terminals will be useful.

normally unix/linux comes up to 6 terminal called tty. you can access terminal by pressing to .
for example if you press then you are opening the default terminal, because you already opened it, it wont show any effect. if you want to open the second terminal (tab/window of shell) press , new terminal (blank screen as usual) will come up and asking you login and password, after you enter login and passwd you will get new terminal or shell windows. for navigate back or open other terminal just change F2 to F3, F4, F5, F6 or F1.