Entities are the heart of a service which are defined in the service.xml in the liferay portlet. It represents the map between the model objects in Java and the fields/column and tables in your database. Once your entities are defined in service.xml, the mapping automatically handle by Service Builder.
For this example, create entity for events.
Heres a summary of the information well enter for the Event entity:-
Local service: yes
Remote service: yes
Below entity example will help to write service in liferay 6.2