Burn the ISO cd image and boot the target PC with it. You should see the “Installer boot menu”: Debian 5 (lenny) Installation - Installer boot menu
Choose the language of the installation process: Debian 5 (lenny) Installation - Language of the installation process
Choose your language: Debian 5 (lenny) installation - Choose your language
Select your keyboard layout: Debian 5 (lenny) Installation - Select your keyboard layout
Choose the hostname: Debian 5 (lenny) Installation - Choose the hostname
Choose the domain name: Debian 5 (lenny) Installation - Choose the domain name
Select your time zone: Debian 5 (lenny) Installation - Select your time zone
Select the partitioning method: Debian 5 (lenny) Installation - Select the partitioning method
Select the disk to partition: Debian 5 (lenny) Installation - Select the disk to partition
Select the partitioning scheme: Debian 5 (lenny) Inst