BMW E64 Subwoofer Activation

I need assistance activating the subwoofer in my 2006 BMW E64 convertible. I replaced the original amp with an OEM amp of the same model. All other speakers are working fine, but the subwoofers are silent.

Requirements:
- Diagnose and activate the subwoofer
- Ensure all connections are secure and functional
- Must have experience with BMW audio systems

Ideal Skills and Experience:
- Proficiency in BMW audio system diagnostics
- Experience with amp installation and troubleshooting
- Access to necessary tools for configuration

Please provide a detailed plan and timeline.