Here’s the instructions to install your SD card ready for the Raspberry Pi.
1. Download and install Win32 Disk Imager from this link:
2. Download Raspbian here: https://www.raspberrypi.org/downloads/raspbian/
Unzip it (this may take a while as its a large file to match the size of the SD card)
3. Plug the SD card into a SD card slot or adaptor for your PC.
4. Start the unzipped Win32DiskImager.exe application
Ensure the correct driver letter is selected for the SD card – double check this is right in Windows Explorer as Win32DiskImager will overwrite the entire drive without warning if the wrong drive is selected!
Select the unzipped Raspbian .img file
Press Write and wait for the program to write the operating system onto the SD card.
5. Once the writing is done plug the SD card into the Raspberry Pi and power it up.