There are an almost infinite number of ways in which a PPP server can be set up. In order to connect to your ISP (or corporate PPP server to access your intranet), you will need to obtain information on how the PPP server operates.
Because you are using Linux, you may have some difficulty with some ISP help desks (and work site based PPP intranet servers) which know only about MS Windows clients.
However, a rapidly growing number of ISPs use Linux to provide their service - and Linux is also penetrating the corporate environment as well, so you may be lucky if you do strike problems.
Section Chapter 11 tells you what you need to know about the PPP server to which you are going to connect - and how to find out the information you need to know.