Attaching test cases to main Jira story using Zephyr Squad

[G subramanyam]

Hi team,

Our team recently started using Zephyr Squad for test management-test cases create/upload. I would like to know the process for attaching (as a subtasks) to main Jira story. 

Currently QA team uploaded the test cases for a story in active Sprint, but they are appearing in backlogs. Do we have an option to add those as "sub tasks"? OR "linking" them is the only option?

Note: I checked their website and couldn't find a demo link for the current version software.