You can run your test cases in different ways: from the Test Cases view and from the Repository tree view.
To run a test case from the Test Cases view
Open the test case and go to the Test Cases view.
Right-click the test case name on the left panel and select Run TestCase from the contextual menu.
All the instances of the test case are executed at the same time. The right panel displays the test case execution results, including history execution information.
To view the execution results of a test instance including the execution history, or the details of a particular execution, click the corresponding [+] button.
From the Test Cases view, you can also run a test instance individually. To do so, right-click the test instance on the left panel and select Run Instance from the contextual menu.