Final answer:
To add test classes to a User Story record, navigate to the 'Test Level' section, click 'Configure Tests', add the tests, and ensure the 'Tested' checkbox is checked.
Step-by-step explanation:
The process of adding test classes to a User Story record, likely within a software development or testing platform. To add a test to the User Story record, you would navigate to the 'Test Level' section and click on '"Configure Tests"'. Once you have added the tests by selecting 'Add New', the 'Tested' checkbox will be checked, indicating that these test classes were indeed included in the test run and therefore will not be excluded from the results.