For almost the whole of our project you need Raspbian OS so now I will explain you how to install it on Windows, Linux and MAC OS!
First of all you need to download Raspbian image and you can find it in the official Raspberry Pi website at this link.

How to install Raspbian

To install Raspbian OS we’re going to use Balena Etcher, this programm is easy to use, user friendly and you can download for Windows, MAC OS and Linux in the same way. Open the website linked before, It detects your OS and you can easily click in the green downlaod button to get the right version of the programm.
When download is finished open the file and install the programm. After that open it and you can flash your SD card in a few second just clicking a button. Insert the SD card in your PC, select the image you want to flash and start flashing process!