Breadboard View:
After I uploaded the Arduino code, the serial monitor looked like the following:
To be honest, I am not sure if that’s what it’s supposed to look like, but since I was seeing words on the monitor, I moved on.
Then, I attached the LED and put commands so that the buttons could control the keyboard. The following is a video demonstrating the result:
https://drive.google.com/file/d/1zPNUwNswW-tV5iCM64bUjiscBg-rTQwR/view?usp=sharing
The LED lit up when I pressed the first button. However, the rest of the four buttons did not give me any input when I opened up my notes app to type something.
On another note, my caps lock was on when the LED was lit — I am not sure why. Also, my mouse started to function oddly — I couldn’t really click left, and I also could not copy and paste using ctrl + c/v.
I also had a lot of port problem, and the Arduino kept saying that I did not have a valid JTAG interface. However, after resetting my Arduino and unplug/replugging the USB cord, the connection issue was solved.
I will continue to work on it and put any updates.