If you need to boot your Raspberry Pi you must download Raspbian OS from ISO file from https://www.raspberrypi.org/downloads/ and then you have two choices for your OS with NOOBS and Raspbian.
1. NOOBS for a beginner if you need to install OS on your Raspberry Pi, NOOBS can select OS for installing eg. Windows 10 IoT, Raspbian, KODI but NOOBS need 30min to install on your Raspberry Pi
2. Raspbian for Linux user only you can download ISO and write to your Micro SDCard and boot your OS with a few minutes.
For this course, you must install Raspbian OS. Okay just click on Raspbian icon and then go the next page.
When you click on Raspbian icon and then you can found 3 choices.
1. Raspbian Buster with desktop and recommended software
2. Raspbian Buster with desktop
3. Raspbian Buster Lite
We recommend you choose “Raspbian Buster with desktop” because this ISO size it’s not too big and you can have Desktop. If you install with Desktop you can remote to your Raspberry Pi with VNC, Teamviewer, AnyDesk or any kind of remote desktop software for doing somethings with desktop environment require. Please click on Download ZIP and waiting for finished.
When you download finished please extract your zip file.
After you extract .zip file you will get .img file for flash to your MicroSD Card.