OPAM is a package manager for OCaml. It builds and manages compiler versions and OCaml libraries for you easily.
The easiest way to install OPAM on your operating system is to use a package manager for your system. e.g apt-get, yum or homebrew.
Update homebrew formulae and install OPAM.
brew update
brew install opam
add-apt-repository ppa:avsm/ppa
apt-get update
apt-get install ocaml opam
wget http://caml.inria.fr/pub/distrib/ocaml-4.03/ocaml-4.03.0.tar.gz
tar xf ocaml-4.03.0.tar.gz
cd ocaml-4.03.0
./configure -prefix installation_path
make world.opt
make install
Once you have OPAM installed, run opam init
and follow the instructions.
Once done you should be able to run the OCaml interpreter from your shell.
$ ocaml
OCaml version 4.03.0
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