To execute the current project use the Run button in the toolbar or Project | Run. By default all open files are saved and a project build is done when you run the project. The output browser will be opened. It is also possible to pass input to the program via this console.
To stop the execution of the program press the Stop button in the toolbar or select Project | Stop. Please note that the starting point of your project which will be executed when running can be configured using Project | Settings.