Debian 安裝程式由一些特定功能的元件組成，它們完成各自的安裝任務。每一元件執行任務時，會詢問一些任務相關的問題。每個任務又有各自的優先級，可以在安裝程式開始時設定優先級以決定哪些問題會被問到。
執行預設安裝時，只有必要的 (高優先級) 的問題會被問到。使得安裝過程可以高度自動化，幾乎不需使用者干預。元件按次序執行﹔至於哪些元件會執行，取決於您使用的安裝方法，以及您的硬體。對於沒有詢問的問題，安裝程式將採用預設值。
如何遇到麻煩，使用者會看到錯誤畫面，並且顯示安裝選單供選擇其它替代操作。如果沒有問題，使用者將不會碰到安裝選單，只需依此回答每個元件的提問。嚴重錯誤提示的優先級為 “critical”，因此使用者總會注意到。
如果在 debian-installer 開始的時候，加上一些啟動參數，它將會影響安裝程式使用的預設值。例如，假設您希望指定靜態網路連接配置 (如果存在 DHCP，將會被採用)，您可以為啟動參數加上 netcfg/disable_dhcp=true。請參閱 節 5.3.1, “Debian 安裝程式的參數” 以瞭解有效的選項。
Power users may be more comfortable with a menu-driven interface, where each step is controlled by the user rather than the installer performing each step automatically in sequence. To use the installer in a manual, menu-driven way, add the boot argument priority=medium.
If your hardware requires you to pass options to kernel modules as they are installed, you will need to start the installer in “expert” mode. This can be done by either using the expert command to start the installer or by adding the boot argument priority=low. Expert mode gives you full control over debian-installer.
For this architecture the debian-installer supports two different user interfaces: a character-based one and a graphical one. The character-based interface is used by default unless you selected the “Graphical install” option in the initial boot menu. For more information about the graphical installer, please refer to 節 D.6, “The Graphical Installer”.
In the character-based environment the use of a mouse is not supported. Here are the keys you can use to navigate within the various dialogs. The Tab or right arrow keys move “forward”, and the Shift+Tab or left arrow keys move “backward” between displayed buttons and selections. The up and down arrow select different items within a scrollable list, and also scroll the list itself. In addition, in long lists, you can type a letter to cause the list to scroll directly to the section with items starting with the letter you typed and use Pg-Up and Pg-Down to scroll the list in sections. The space bar selects an item such as a checkbox. Use Enter to activate choices.
Some dialogs may offer additional help information. If help is available this will be indicated on the bottom line of the screen by displaying that help information can be accessed by pressing the F1 key.
Error messages and logs are redirected to the fourth console. You can access this console by pressing Left Alt+F4 (hold the left Alt key while pressing the F4 function key); get back to the main installer process with Left Alt+F1.
These messages can also be found in /var/log/syslog. After installation, this log is copied to /var/log/installer/syslog on your new system. Other installation messages may be found in /var/log/ during the installation, and /var/log/installer/ after the computer has been booted into the installed system.