- Unpack , copy files in : "your-halflife2-directory\hl2\cfg"
- In game press "right Shift + F1" to activate menu , chose your AI options and play.
This may rebind several custom controls if you've set any up. Take a look at config.cfg to ensure your keyboard layout will still work as expected. If you've never made customizations to any of those files or keyboard controls, you don't have much to worry about.