[Haskell-beginners] Can't install Haskell platform on Mac OS X El Capitan

Hi, I’m trying to install Haskell on Mac I have OSX El Capitan so I downloaded from https://www.haskell.org/platform/ the Download (64 bit) (10.11). The installer runs, however, when I type into terminal ghci I get ghci -bash: ghci: command not found “which ghci” it just doesn’t return anything. Thanks, Daniel