Before you can use PostgreSQL you need
    to install it, of course.  It is possible that
    PostgreSQL is already installed at your
    site, either because it was included in your operating system
    distribution or because the system administrator already installed
    it.  If that is the case, you should obtain information from the
    operating system documentation or your system administrator about
    how to access PostgreSQL.
   
    If you are not sure whether PostgreSQL
    is already available or whether you can use it for your
    experimentation then you can install it yourself.  Doing so is not
    hard and it can be a good exercise.
    PostgreSQL can be installed by any
    unprivileged user, no superuser (root)
    access is required.
   
    If you are installing PostgreSQL
    yourself, then refer to the PostgreSQL 7.3 Administrator's Guide
    for instructions on installation, and return to
    this guide when the installation is complete.  Be sure to follow
    closely the section about setting up the appropriate environment
    variables.
   
    If your site administrator has not set things up in the default
    way, you may have some more work to do.  For example, if the
    database server machine is a remote machine, you will need to set
    the PGHOST environment variable to the name of the
    database server machine.  The environment variable
    PGPORT may also have to be set.  The bottom line is
    this: if you try to start an application program and it complains
    that it cannot connect to the database, you should consult your
    site administrator or, if that is you, the documentation to make
    sure that your environment is properly set up.  If you did not
    understand the preceding paragraph then read the next section.