Something you need to know about the shift register

What is a shift register?

It's technically an output shift register. In other words, it receives data serially and outputs it in parallel. In practice, this means that we can quickly send a bunch of output commands to the chip, tell it to activate, and then send the output to the relevant pins. Instead of going through each pin, we can simply send the desired output as a single byte or more to all pins at once.

If that helps you understand, you can think of a shift register as an "array" of digital outputs, but we can skip the regular digitalWrite command and just send a series of bits to turn it on or off.

How does it work?

The shift register we'll be using - the 74HC595N included in the Oomlout starter kit - requires only 3 control pins. The first is the clock - you don't need to worry too much about it as the Arduino serial library controls it - but the clock is basically just an on/off pulse that sets the speed of the data signal.

The latch pins are used to tell the shift register when the outputs should be turned on or off based on the bit we just sent, i.e. latch them in place.

Finally, the data pin is where we send the actual serial data in bits to determine the on/off state of the shift register output.

The whole process can be described in 4 steps:

Sets the data pin of the first output pin on the shift register to high or low.
Pulse the clock to "shift" the data into the register.
Continue to set data and pulse out pulses. clock until the desired state is set for all output pins.
Pulse the latch pin to activate the output sequence.
accomplish
You need the following components object for this product:
7HC595N shift register chip
8 LEDs and appropriate resistors, or whatever you want to output to anything
The usual breadboard, connectors and a basic Arduino

Follow the link below to learn more about the shift register.
https://www.easybom.com/blog/a/cd4015-shift-register-circuit-pinout-and-application