Better to start a separate thread for each question -- it gets very confusing when we answer three questions in one thread.
You may find LQ's How To Ask a Question
helps you ask an effective question.
The PATH you get is not set when booting but when logging on. Exactly how depends on which shell you are using. Do you know? This command is a rough guide
Regards networking that varies from distro to distro. Which distro are you using? What hardware do yu use to connect to the Internet -- a standalone modem/router? Is it already set up and working? Generally wired is easier than wireless so better to get that set up first. Is your computer wired to a working modem/router? What is the output from