Hello,
I am very happy that some of your queries were solved,
Since you have enabled the slider, now you will have to go to
Dashboard => Appearance => Customize => Featured Slider =>Slider Type
Then you will have to select slider type as featured category,
Then you will have to select the category, this will be the category that contains posts that displays their featured images in the slider
Finally you will have to assign the number of slides to show on the slider.
For the area besides the slider you will have to go to,
Dashboard => Appearance => Customize => Widgets=>Slider Right Widget Area
Then you will have to add a widget, WordPress by default has many widgets, but except that the theme also provides you with their widgets like “Magzimum Special Posts”, “Magzimum Category News”, “Magzimum Social” etc.
You can add any widget you think is right for your website on that area,
I hope this helped,
Best regards.