Automate.video calculates automatically scene durations based on the content of your slide.
However, sometimes you may want to override that calculation.
To do so, you just need to indicate in PowerPoint the duration after which automate.video should go to the next slide.
Go to the "Transitions" tab, click on "Advance Slide" section and enter your duration in the "After" field.
And then just upload your file to app.automate.video
That's it, now the scene duration information will be taken from PowerPoint.