Describe a Test Case in the 'Summary' field. Summary must include functionality name and short summary of the Test Case (in case of complicated Test Cases)
In the 'Description' field you can also add more details e.g. user story or leave it empty if 'Summary' field provides enough information
In 'Attachment' field you can add screen shot or short movie to help localize the issue
'Label' field should contain key words used for search purposes
If the Test Case is meant for an automated test, add a link to automated test code in 'Automated' field
This should open up the Test Case page which should look like
Scroll down to the Test Execution Section and click the E button on the rightmost end of the row containing Test Cycle value as Platform 2.0 Release Tests