The main means that people use to install packages on their system is via a program called apt-get, from the apt package. Note that the actual program that installs packages is called dpkg. However, this package is more of a low-level tool. apt-get will invoke dpkg as appropriate; it is a higher-level too, however, because it knows to install other packages which are required for the package you're trying to install, as well as how to retrieve the package from your CD, the network, or wherever. APT must be configured, however, so that it knows where to retrieve packages from. The helper application which assists in this task is called apt-setup. The next step in your configuration process is to tell APT where other Debian packages can be found. Note that you can re-run this tool at any point after installation by running apt-setup, or by manually editing /etc/apt/sources.list. If an official CD-ROM is in the drive at this point, then that CD-ROM should automatically be configured as an apt source without prompting. You will notice this because you will see the CD-ROM being scanned. For users without an official CD-ROM, you will be offered an array of choices for how Debian packages are accessed: FTP, HTTP, CD-ROM, or a local file system. You should know that it's perfectly acceptable to have a number of different APT sources, even for the same Debian archive. apt-get will automatically pick the package with the highest version number given all the available versions. Or, for instance, if you have both an HTTP and a CD-ROM APT source, apt-get should automatically use the local CD-ROM when possible, and only resort to HTTP if a newer version is available there. However, it is not a good idea to add unnecessary APT sources, since this will tend to slow down the process of checking the network archives for new versions. If you plan on installing the rest of your system via the network, the most common option is to select the http source. The ftp source is also acceptable, but tends to be a little slower making connections. The next step during the configuration of network packages sources is to tell apt-setup which country you live in. This configures which of the official Debian Internet mirror network you connect to. Depending on which country you select, you will be given a list of possible machines. Its generally fine to pick the one on the top of the list, but any of them should work. If you are installing via HTTP, you will be asked to configure your proxy server. This is sometimes required by people behind firewalls, on corporate networks, etc. Finally, your new network package source will be tested. If all goes well, you will be prompted whether you want to do it all over again with another network source.