The first steps after the installer is to get logged into your machine. The console login might look a tad bit alien to you, but it operates much in the same way that the display managers do. Simply enter the username you picked for yourself in the installer, and you will have a command line from which to work from.
To get networking up and running, first run:
This should show you what network interfaces you have up and running on your system. At bare minimum, you will have the "lo" or loopback device, but you should see another device that starts with eth, most likely eth0. Execute this command:
sudo dhclient eth0
This will request an IP address from your dhcp server and configure the interface. You will need to run this command every time after you log in, unless you make the connection permanent. To make this network connection permanent, or to configure a static IP address, see the "interfaces" man page:
That will explain in detail how to set up networking on Ubuntu and Debian.
Now that we've settled a bit into logging in and command line networking, for the next article we will take a look at a more controversial topic, what to install for the graphical environment.