Dear Kalai,
I believe you will definitely enjoy working on this framework.
However firstly let me know what database you are willing to use.
Is it derby, mysql,etc..
In order to configure the database you need to have the database driver made available inside framework/entity/lib/jdbc folder.
Then whatever database you are willing to use give the details for the database & its connection in entityengine.xml for particular one eg localderby, localmysql etc.
Just run the framework using java -jar ofbiz.jar once, & for the first time the database structure gets automatically populated. If you wish to load the seed demo data you can write the command java -jar ofbiz.jar -install -readers=seed,demo,ext
You can then use the editor for the corresponding database to view & manipulate it.
Hope it would help you.
Kind Regards,
Vivek J