For automated tests, another requirement for test creation is a Source Control Profile. Automated tests in Silk Central actually represent test scripts that are located in source control systems, which are accessed via such source control profiles. Both product and source control profile information are specified on Test Container level, which therefore represents the top-hierarchy node of a test assets structure. Within a test container you can then use folders to structure your test assets according to your testing needs and your process.
Remember that although you can have multiple test containers, one execution plan can execute tests of only one test container due to the test result/build/version relation. Therefore, design your test asset structure according to which tests you want to execute together within one execution plan.