Sign it using your own Symbian developer certificate from OPDA?

To sign your application using your own Symbian developer certificate from OPDA, first, ensure you have the necessary tools installed, such as the Symbian SDK and the signing utility. Next, obtain your developer certificate and key files from OPDA. Use the tool provided in the SDK to sign your application by specifying your application file along with the certificate and key files. Once signed, your application will be ready for installation on Symbian devices.