I planned to build a multi LED project but realized that my Arduino Nano wouldn’t be able to individually turn on and off many LEDs. I guess I have a little more then 10 pins on my Nano and I wanted to individually power on at least 30 LEDs.
So I conducted some research and found a new component: the shift register.
I haven’t had time to try the shift register, but my understanding is that you provide some kind of serial signal as input to it, and it will turn on or off pins according to the signal.
(After some more research I found a much better product for my problem: the LED strip with individually addressable lights with RGB.)