When the NetBeans IDE builds your application, it creates a MIDlet
Suite consisting of the usual JAD and JAR files. These files, stored
in the /dist folder of the project are used to
install the application onto your Series 40 phone. Remember to use
obfuscation - using the LWUIT library without obfuscation makes the
Series 40 MIDlets in practice too big to be installed on Series 40
phones (where the maximum JAR size limit is 2MB). Obfuscating decreases
the library to contain only the classes that your application needs.
Obfuscation can be set in your project's Properties and there under Build > Obfuscation. If you have not set it up, there is a prompt to download and install ProGuard.
You can deploy your application from the IDE (right-click on the project and select Deploy) or locate to the binary in Windows Explorer and send it to the device using Nokia Suite or via Bluetooth.