You can build applications for multiple targets. By default, when you run the application on a target, you also build and deploy it to the target, first. However, you can also perform each operation separately.
To check that the application code can be compiled and linked for a target, you can build the project. The build errors and warnings are displayed in the Build Issues output pane. More detailed information is displayed in the Compile Output pane.
To build an application:

For more information on the options you have, see Specifying Build Settings.
The tool chain for building applications locally on the development PC for the Symbian Device target is only supported on Windows. If you develop on Linux or Mac OS, you must use the Remote Compiler interface to a compilation service at Forum Nokia. For more information, see Building with Remote Compiler.
If you cannot build the application for a Symbian device, check that:
Qt Creator does not create release configurations for the Symbian Emulator target, because Symbian Emulator supports only debug builds.