1- Install Half-Life ( you will need PowerISO or DAEMON Tools to do it )
2- Istall the update for Half-Life
3- Install Counter-Strike 1.3
4- Install PODbot ( to play with bots if you want )
6- Open one of the Keygens and get a CD-Key and copy it
7- Open Counter-Strike 1.3 and it will ask you for the CD-Key, Paste it and have fun