First of all, you have to create your application and connect to the database, for that you must click on "Application builder" and then click "configure database" [Fig. 1] and put information from your database [Fig. 2]
Open eclipse, it is automatic create the file with the the same name of your connection (hibernate_app_pg_1). Open the file and map yours classes [Fig. 3]
Now, just create your class Teste and Voilá [Fig. 4] And don't forget put your connection name on your classe [Fig. 5]
Then you can see your table created in your database [Fig. 6]