When someone gives you their web address, it generally takes you to their website's home page, which should introduce you to what that site offers in terms of information or other services. From the home page, you can click on links to reach other sections of the site. A website can consist of one page, or of tens of thousands of pages, depending on what the site owner is trying to accomplish.
We'll tell you how to create and improve your website in further articles, but the main thing to remember is this: A website is a means of communication, and it is only successful when its message is received by the intended user.