You can execute either a selection of test cases in your scenario, or the entire scenario. To execute the full scenario click 'Run all'. The execution window, which you already know from test executions, opens and you can execute each test case step by step.
To execute a selection of test cases, select the test cases and click 'Run selected'.
You will find information about the latest local executions in the test scenarios. To see them, click on 'Test Cases'. More information regarding the latest executions can be found in the 'Executions' tab. Here you find all execution in a table view. You can then continue, abort or finalize the executions or set them as irrelevant, just as you can with the execution results in the test cases themselves.
If you want to see even more detail, double click an execution.