When you choose to install a game the first time, you'll get to choose where to install the Steam library. Then, if you want to install a game on another drive, you'll get to choose where to install a second version (lighter?) of Steam containing the usual directory ~/Steam/SteamApps/common where your game will be installed. Afterwards, if you choose one of those directories for your other games, they will be installed directly in the "common" folder, as usual.
I had Steam installed on the C drive once, in C:\Program Files; I could have chosen to install it in C:\Program Files/Mes Jeux if I had wanted to and Steam would have installed itself in "Mes Jeux". Then I chose to install other games on my H drive in "H:\Jouer\" and had no trouble at all selecting "Jouer" as the installation folder for the new Steam directory.
In short, you can have one, only one, Steam library on each of your drives.
Now, all my games are installed on the H drive.