You can execute Test Runs one time or regularly by configuring a schedule for Test Runs. See: Schedule Test Runs.
You can also execute Test Runs manually by following these steps:
Go to your Project > Test Execution > Test Run List.
Click on the Run icon for manual execution.
View the status of Test Runs
After executing Test Runs, go to Test Execution, then select Test Run Calendar to check their status in a calendar view.
Click on a Test Run on the calendar to see its summary.
If a Test belongs to a Test Suite, you can also see a summary of the Test Suite here.
Next step: Manage Test Runs by Release.