Unable to edit audio in an imported mp4 video

Problem: I have downloaded a youtube livestream recording as mp4 file and I want to edit it in
Active Presenter. I want remove the audio in a portion and record fresh narration. How to do this.?

ActivePresenter Version: Required.ActivePresenter Pro Edition
Version 8.0.6 (Released: 2020.04.28)

OS: Required. Window 10

Notes:

Hi,

Firstly, you need to insert that video into your project.
Then, in the Timeline pane, define the part that you want to remove audio > select the Adjust Volume button > select Mute:
1

Finally, click on Record Narration button to record you own narration:
2

For more information, please take a look at the below article:

Regards,
Yen