Note that on UNIX both your password and your username are case-sensitive, so you should be careful not to confuse upper and lower case letters. The following desktops are available. Just press the return key, or select OK with the mouse to keep this default. Click with the right mouse button on an empty area of the screen, select programs and then terminal. Both of these will get you netscape.
Opinions vary as to which is the better program.
Many people use pine because it is common enough on many UNIX systems to form a standard, and it is quite powerful and customizable. To get help on most commands, use the man command, as in man dtpad to get help on the dtpad editor. In either case the system will prompt you whether you want to continue logging out. If you are going to make much use of the UNIX system, it is worth getting books on UNIX and X-windows and studying them.