Did you mean network-manager-applet-0.8.3.998.tar.bz2? That is a source package which needs to be extracted and compiled. Unless you really, really need the latest version, I recommend you installing the network-manager-gnome from the package manager. It integrates better and will be updated automatically.

To extract the package, you need to open a terminal and:

1. Change the directory to the directory containing the .tar.bz file: cd /path/to/dir


2. Extract the bzip2-compressed tarball: tar xjf Manager-0.8.3.998.tar.bz2


3. Change the directory to the newly created directory (use ls to get the directory listing). cd network-manager-applet-0.8.3.998


4. Run ./configure. If you need to have a package installed, you'll be informed here.


5. Run make to start compiling


6. Run sudo make install to install

Again, it's recommended to use the package from the package manager, not to compile it yourself unless you really need to.