Raspbian 9 (Stretch) is the latest version of Debian for the Raspberry Pi.
Here is how I installed it:
Download the Raspbian Stretch Lite installation file from here.
We need a tool to write the OS image to a SD card. I used Etcher which can be installed from here.
Insert a SD card of at least 4GB capacity into your computer. Use Etcher and install the zip file to the SD card.
Eject the SD card. Remove it and plug it back into your computer. Create an empty file named ssh in the root directory of the SD card. This will enable you to SSH to your Raspberry Pi.
Insert this SD card into the Raspberry Pi board. Connect your Pi to your home wireless router with a Ethernet cable. You can also connect your Pi to your TV or computer display with a HDMI cable. Power on the Pi.
You can see Raspbian booting up on your TV or display. At the end it displays what IP address was assigned to it by DHCP. You can also figure out the IP address from the admin console of your wireless router. Let us say the IP address is 192.168.0.10.
SSH to the IP address of your Pi. The login is pi and the password is raspberry.
$ ssh firstname.lastname@example.org
You are logged into the Pi now! Change the password using the passwd command.
Update the packages using these commands:
$ sudo apt update $ sudo apt upgrade
Your Raspbian 9 is all set now for your use.