To install PostgreSQL use your Linux's package system or install it manually by downloading it from http://www.postgresql.org/download/ and following their instructions.
With PostgreSQL installed and started, create a database named eHour by executing:
Install eHour database
With the ehour database created, the next step is to create and initialize the datamodel.
sql/postgresql/install directory there's a
fresh.postgresql.sql script which contains the datamodel and default data.
Execute it by running the following command:
psql -U ehour -h localhost ehour < fresh.postgresql.sql
The standalone distribution does not contain the fresh.postgresql.sql file. The file is available at at this location.