At this point you should have your hard drive partitioned and these partitions assigned to what areas they'll be housing.
Now, comes the point in the process to install the Linux kernel. You can choose additional parts to add to the kernel, known as modules, to better use your hardware. Debian does a pretty good job of auto-detecting what you have, so there shouldn't be any need to touch anything here. People who know that they're going to have to use foreign character fonts may want to add additional support for font sets.
At this point, you'll have to choose a 'hostname' or name for your computer. Use whatever naming scheme is comfortable for you. After, you should choose a 'domain' name. Even if you're not running an Internet server and even if you don't have a network you should choose a name as if you had one. Normally if you were in fact a server providing Internet services, you would choose a name and append .com, .net etc on the end. I would, of course, be a name registered with an official domain name registry. In the case of a single machine or a network that's connected to the outside only by way of a dial-up connection, you should choose a single name without the dot extension. Now you should enter your ISP's domain name server IPs. Each block (the four numbered set separated by periods) should be separated by a space.
Now, as we're installing from a CD/DVD, you should choose 'CD-Rom/DVD' for the installation procedure. You should also choose the settings 'make system bootable'.
Your hard disk is basically a piece of metal with a metal disk flying around in it at incredible speeds. It essentially does nothing unless you tell it to. At this point, we're going to tell it to boot up the Linux operating system. If you're contemplating a dual-boot system, you can also tell it to ask you to choose from different operating systems at boot. Debian uses a program called 'GRUB' to do this. Later, you can actually make alternative versions of the Linux kernel and have GRUB boot them. Right now, your safest bet is to install GRUB in the 'master boot record' when the install program asks you. The \"MBR\" is a little slice of the hard disk pie reserved for moments like this!
The program may now ask you to create a rescue disc. These will come in handy. For example, I have often made the fatal mistake of *not* correctly configuring GRUB when I have made a new Linux kernel (yes, you can make them from scratch!) and my system has become unbootable. You can always rely on a rescue disks to get you out of this situation.
OK, now's the time to reboot the basic system that Debian has installed. You need to remove the CD from the drives. It might be a good idea now, as your machine reboots, to go back into the BIOS and set it back for the machine to boot from your hard drive first (instead of from your CD drive). But at least make sure to remove the CD/DVD or else it will boot the CD/DVD again and start the install process again.