Download NOOBS from https://www.raspberrypi.org/downloads/noobs/. The NOOBS distribution is for new users who do not possess much knowledge about Linux systems and Raspberry Pi boards. As the official page says, it is really, "New Out Of Box Software." There are also preinstalled NOOBS SD cards that you can purchase from many retailers, such as Pimoroni, Adafruit, and The Pi Hut, and of course, you can download NOOBS and write your own microSD card. If you are having trouble with a specific distribution, take a look at the following links:

• Full guide: https://www.raspberrypi.org/learning/software-guide/
• View the video: https://www.raspberrypi.org/help/videos/#noobs-setup

The NOOBS operating system contains Raspbian, and it provides various other operating systems available to download.