-- Install it to Steam/SteamApps/youremail/half-life/hostileintent
Make sure it does not end up in half-life/hostileintent/hostileintent
*NOTE* If you don't see a "Half-Life" directory, just create it!

-- Copy the files in the Hotfix to the HI directory whatever files it asks to overwrite click "yes".

-- If you can't get nightvision to work, you must bind a key to nightvision. Type this into your console (without the <>'s):
bind nightvision

-- If you can't get voicecom to work, you must bind a key to +voicerecord in your console:
bind +voicerecord