The IC can work from 3V to 15V, but normally powered with +5V to the Vdd/Vcc pin and the Ground/Vss pin is connected to ground. We have 7 output pins naming from Out A to Out G which is directly connected to the 7-segment display. The clock inhibit pin (pin 2) has to be held low (ground/0V) so that the clock signals can be sent to the IC also the Enable Input pin (pin 3) should be made high (+5V) so that the output pins (Out A to G) can be made active.
The 7-segment pins will increment the count by one number each time when the clock pin (pin 1) is made high. This clock source can either be obtained from a 555 IC or any other digital IC which is TTL compatible. They simply have to generate a pulse of low voltage 0V and high voltage 5V. In the circuit below I have used a clock source of 1Hz to increment the count. So the number will get incremented for every (T=1/F) 1 second.