Gosh......here we go.
Alright, basically Steam is a program which allows you to play games like Half-Life, Counter Strike, Half-Life 2, Day of Defeat etc etc. But in order to play a specific game you have to buy it
right. [ Lets not go cheeky ]
After you've bought the game you'll get a specific serial number don't lose it.
Once you've made a
Steam Account activate Half-Life 1 using that serial. This will enable you to play Half-Life 1, from Half-Life 1 comes its modifications such as Earths Special Forces, Natural Selection and so on.
To download Steam, just go here:
www.steampowered.com
Just look around for the download link, but let me repeat myself, you must
buy half-life there is no other way. There are 2 ways of getting half-life
1) Through stores
2) Through Steam.
Since Half-Life 1 is SUCH and OLDDDD GAME, I highly doubt it you'll be able to see it in the shops, but have a look anyway.
-GuZzie