You're asking two different questions.
Exporting your $PATH: presumably you want to add a new directory to your $PATH? To add a new directory, /foo to your $PATH you'd use the following: "export PATH=$PATH:/foo:". Edit: obviously this assumes you're using Bash (or another shell with the same syntax).
Tarballs: you'll need to extract the contents of the archive before doing anything else. Read the tar man page for details on how to do this.
Last edited by Nylex; 03-15-2008 at 02:40 PM.