Test plans can be used optionally to group different test runs, or test suites, in case your project is of multiple Test Suites type (read more about Project types here). To create a test plan, navigate to your project's Test Runs & Results section and select "Add Test Plan".
You can then associate your test plan with references and a milestone, as well as:
- Adding multiple test runs (read more here)
- Reruning an existing test plan
Once your test plan is created, you can finally start on your test runs.