added step for copying config_default.php to config.php

INSTALL

@@ -8,9 +8,11 @@ overview of how to install SquirrelMail.
 3.  Unarchive SquirrelMail in a subdirectory that is accessable by the
     web server.  EX: /home/httpd/html/squirrelmail-0.1
 
-4.  Edit the config file, config/config.php
+4.  Copy the config file config/config_default.php to config/config.php.
 
-5.  Change the permissons for the "data/" directory so it's writable to
+4.  Edit the config file, config/config.php for your network.
+
+6.  Change the permissons for the "data/" directory so it's writable to
     the web server.  Under Red Hat Linux 6.0, this is done by:
 
     chown -R nobody data
@@ -19,5 +21,5 @@ overview of how to install SquirrelMail.
     "nobody" is the user and group for the apache server for this
     example.
 
-6.  Point your browser to the location you specified in step 2.
+7.  Point your browser to the location you specified in step 2.
     In this example, it's:  http://YOURHOST/squirrelmail-0.1/index.html