If your project is a plain JAVA application, all you have to do is add the core TESTARE classes to your development classpath, and start using it just like you would use JUNIT.
If you're developing a server side j2ee application you'll need to integrate the TESTARE ejb agent or other customs agents you might develop to your enterprise application.
If your tests will call other EJBs or use classes deployed within the j2ee application, you may have to update the ejb agent's class path in META-INF/MANIFEST.MF - in order to tell your container's class loader what classes to make available to the deployed scenario runners.
Then you can simply start writing tests by including the core and ejb client jars in your compile and client side execution class path.
CATION: including the test framework agents in your enterprise application is only recommended for testing environments. Deploying it on production environments can lead to serious security issues.