1. Install Wifi Shield Firmware
For some reason, I had to manually download the wifishieldfirmware.
Still received the fatal error of missing spi.h – https://www.reddit.com/r/arduino/comments/330k8i/compilation_error_due_to_missing_spih/
Following the comment from this reddit entry, I just copied spi.h inside the main program. But looking to find a way that solves the problem. May need to reinstall the arduino.
Though I didn’t get to use github except for downloading the whole file as a zip, this tutorial seems to come in handy for all the first time users for the github – https://youtu.be/E8TXME3bzNs