I formatted my SD card to fat32 using GParted and copied all the files from the official NOOBS Lite download: https://www.raspberrypi.org/downloads/noobs/. I unzipped using unzip command on the terminal. When I turn on the rainbow appears and the Pi gets stuck there. Red LED is on, green turned off after a few seconds. Don't know if I did something wrong or my card is broken. Appreciate your help.
The Boot Problems Sticky contains detailed troubleshooting steps.
Using NOOBS just makes fault finding harder.
The rainbow screen is due to missing (or obsolete) firmware.
I suggest you use Etcher to install Raspbian to a SD Card (like the vast bulk of us).
If you REALLY want to install NOOBS, make sure you have the LATEST version and follow the Foundation instructions =>
Visit the SD Association’s website and download SD Formatter for Windows or Mac.