As a new user, an orientation may be useful. I won't try to provide that orientation in this short space, but perhaps I can explain some of the basics and provide some references that will get you started.
man is simply a command in Linux/Unix. Its function is to display documentation relevant to another command. For example,
man ls will display documentation for the
ls command. Wikipedia has a decent article on man page that provides some history, and a glimpse at what goes on "behind the scenes". It's probably worth a few minutes of your time to read this article.
Second - As you've noted, man pages are divided into sections. However, most man pages do not have all of these sections. In general, a man page will have only those sections that are appropriate to the command - most man pages have only one or two sections. You can usually learn what sections are available for a man page using this command:
man -f <command>
# for example:
man -f mount
mount (8) - mount a filesystem
mount (2) - mount filesystem
Third - You will learn how to use man pages through a combination of reading and practicing. The ideal place to start is to open a terminal, and enter the following:
Yes - there is a man page about the
man command! This will explain the various options and arguments available. N.B. the documentation in a man page will not always be completely clear to you! This is why practice is important.
Finally - Searching the Internet is usually a productive method for getting answers to specific questions, or finding tutorials and examples. For example, this search on how to use linux manuals turned up this potentially useful Linux
man Tutorial. When searching, you should remember that Unix/Linux is an diverse area of practice that is constantly changing. It happens frequently that users find out-of-date information and deprecated resources. There is no magic rule to avoid that, but it often helps to check the publication or revision date of the article and perhaps the relevant distribution (i.e. Ubuntu, CentOS, etc) to find information most relevant to your use case.
And speaking of searching: There is one other command closely related to
man that you should learn - the sooner the better. That command is
apropos... and as usual, learn more with