how do i do this?

My friend told me about this game but hes away on a trip so i don't know what to do. I need to know where to download and how to install. If you can help me that would be great.

www.esf-world.com in the navigation u only have to click on releases. then u get a list of all esf releases(okey some alphas are not there...). just download the 1.2.2 full or lite version

ok so whats the diffrence between them and after i download it how do i install it?

http://www.esf-world.com/main.php?content=fileinfo&file_id=25162

you want that one

To install it - make sure you have steam on (www.steampowered.com) and a valid halflife cdkey.
Then install steam, register your cdkey with it then run halflife once, then install esf using the installer.