The description on that page says where to put it.
where it says YourDisk:\Steam\steamapps\YourUserName\Half-Life\
you may be putting the contents into this folder
C:/Steam/steamapps/example@example.com/Half-Life/
Also, since they said Half-Life and not Half-Life 2 I think you need to have Half-Life(theFirste) installed and run once so the folder gets created.
The contents of the zip contain folders, drop the folders themselves right into that Half-Life directory. It shouldn't overwrite anything you already have in there.

Originally posted by DarkCrystalMethod:

The description on that page says where to put it.
where it says YourDisk:\Steam\steamapps\YourUserName\Half-Life\
you may be putting the contents into this folder
C:/Steam/steamapps/example@example.com/Half-Life/
Also, since they said Half-Life and not Half-Life 2 I think you need to have Half-Life(theFirste) installed and run once so the folder gets created.
The contents of the zip contain folders, drop the folders themselves right into that Half-Life directory. It shouldn't overwrite anything you already have in there.

Thanks

What does it mean by put into "your disk" ?

"Your Disk" is whatever hard drive you installed steam onto.
Windows computers have a main "C:\" disk.
The instructions are to extract the zip file and then copy the contents (one folder simply named "zombie") to the correct location (within the Half-Life folder).