well on the front news it said that they relized people were trying to but I suggest buying HL cuz that way you can get any mod for steam.
1. Make sure you have Half-Life (its cheap these days so its an easy buy but some places don't have it go to a place like EB games to be sure)
2.Make sure you have downloaded and installed steam available at
www.steampowered.com
3. Go to the Downloads/Files part of ESForces.com find a suitable mirror for download
4.Download the most recent version of ESF (1.2.3)
5.Open the file and when you install it be sure to install it to Program Files/ Steam/ Steamapps/<your e-mail adress here>/Half-Life
When it installs it your esf directory should be right here
Program Files/Steam/Steamapps/<your e-mail adress here>/Half-Life/esf