Single digit, Seven segment Numitron program and pcb design needed.

I found an RTC library for a ds3231 and it has a Test sketch and a settime sketch. When i load the test sketch i can open up the serial monitor and it shows the rtc reading every second. So it seems like they are working.

When i load the set time sketch. The serial monitor is blank. Do i need to set the time within the Arduino IDE or within the serial monitor?