To " I want to make Digital Master Clock which will connect to Ethernet to drive slave clock":
What you might need:
7 Segment displays,
Arduino,
(Ethernet/Wifi shield, if your controller board doesn't have an internet access way or just get the clock module, which is cheap https://howtomechatronics.com/tutorials/arduino/arduino-ds3231-real-time-clock-tutorial/)
A power supply.
You do not need the 74HC595 to controller the 7-segment display.
I can help you with the code, but it depends on what elements you get for the project.