Might be a stupid question but

how do i download esf for steam?
the steam pack one doesnt work on the download page

just download any esf and then install it on steam. it will automaticly find the half life folder in steam, its will be like "c:/program files/steam/steam apps/*your user name*/halfe life/esf". hope that helps. you dont need any additional files, just any working esf install.

and it will be under the third party games, btw