24 second shot clock

can you give me all the details about 24 second shot clock????we have the following materials:

IC 72LS192
555 timer
resistor
150 ohm, 1 watt
33K,1 watt
10K, 1 watt
capacitor-0.1 microFarad (ceramic)
IC 72LS00(NAND GATE)
7-segment(common anode)
supply voltage-5V

ALso what is the PCB layout of this project????thanks....pls. i need your reply as soon as possible

Can you give the datasheet of 72ls192??? i could'nt find it on the net.....or is it 74ls192???