This is digital clock schematic diagram. This circuit is quite complex and quite difficult for a newbie because this circuit uses IC with some a complicated connections. The voltages that supplied to the circuit are divided in two lines.
The voltage +5VA supplies all IC except the IC9 until IC13 and is supplied with voltage in case of break of network voltage. On the other side, the voltage linr of +5VB only supplies the IC9 until IC13 and display and is interrupted in case of interruption of network voltage, it is to ensure the economy of battery.
You can find the complete explanation include the component part list on the original page.