Unlocking audio from video on timeline

Hi, can anyone please inform me on how to unlock the audio track from the video so that I may add another audio in place of the original? I have tried clicking on the magnet and the chain-link icons but nothing occurs. I feel that there is a simple answer and I am omitting one or more actions on this. Any help will be greatly appreciated.

As a new user, your first course of action should be to complete some Resolve training. The Beginner's Guide and Advanced Editing are an excellent groundwork to get you moving smoothly.

https://www.blackmagicdesign.com/produc ... e/training

Make sure the video clip is not selected (no red outline around it), then click on the chain link icon to deselect it so that it is dark grey. You should now be able to select either the video or audio separately.