Light up LEDs by using buttons to control the data, clock, and latch pins on a 74HC595 Shift Register.

This is a simplified version of the circuit built here.

 

The pinout of the 74HC595 and this YouTube video helped me understand how the shift register works in general.

 

I simplified the original circuit by removing the buttons to the Clear pin (pin 10) and the Output Enable pin (pin 13). Instead, wire Output Enable to ground and Clear to power.