It is pretty straight forward, fist you need to download the operating system for your Raspberry Pi – you do that from raspberrypi.org.
Being on a mac I used mac tutorial for instaling the operating system on the Raspberry Pi SD card but if you use a windows or linux you can find the on the website as well.
Nice terminal commands to know:
Will take you to the basic setup of the RASPBIAN
$ sudo raspi-config
If you disable the RASPBIAN to boot into the visual userinterface X-server you can enable it by typing