Download and install Postgres. After you have installed it, you will need to create a user root with an empty password. You can do this by changing into the Postgres directory and typing ./createuser root. The system will ask you two questions. Answer the first with yes and the second with no. The user should be allowed to create new databases. You will then need to create a new database. Do this by typing createdb testdb.
Test Postgres by starting the server (type ./postmaster). Open another console, change into the Postgres directory, and type ./psql -U root testdb to initiate a connection with the database server. From there you should be able to execute SQL statements.
To use the plugin with Postgres, you will need to change the plugin parameters appropriately. The following are the settings I use with Postgres:
| Database User Name | root |
| Database Password | {empty} |
| Login Database Name | testdb |
| JDBC Driver | org.postgresql.Driver |
| JDBC URL | jdbc:postgresql://localhost/ |
See Using the Configuration Utility for more information on how to change parameters.