Your applications are run (and debugged) based on a launch configuration. When you create new Flex and ActionScript applications, a launch configuration specifies the location of the built applications files and the main application file. You can modify the launch configuration or create custom launch configurations. For more information, see Managing launch configurations.
Running your projects opens the main application SWF file in your default web browser or directly in the stand-alone Flash Player. For information about changing the default web browser or running and debugging with the stand-alone Flash Player, see Changing the default web browser and Running the application SWF file in the stand-alone Flash Player.
You can run your projects in a number of ways in Flex Builder. For example, you can use the Run command, which is available from the workbench main menu and toolbar, from the Flex Navigator view, and code editor pop-up menus.
Run project with default Flex application launch configuration
If your project is not built yet, Flex Builder builds and runs it.
Your application appears in your default web browser or the stand-alone Flash Player.
You can run and debug any project files that have been set as application files. For more information see Managing project application files.
Create custom launch configuration
Run other application files in your project
Run a custom launch configuration
From the main menu, select Run > Run > Other.
In the Create, Manage, and Run Configurations dialog box, select an existing custom launch configuration or create a new one. See Managing launch configurations.
The Run command works a bit differently in the plug-in configuration of Flex Builder. Instead of running the currently selected project, it runs the most recently launched configuration. You can also select from a list of recently launched configurations.
Run the last launched configuration
Click the Run button on the main toolbar.