Hello @OFFMONEY,
The Extra sidebars in the Magazine Plus Pro theme is designed to be used for desired post / page only in the primary and secondary widget area ( Sidebars ) in the theme in the pages / posts individually.
After Adding your desired widgets, you can set to display the widgets from the Page / Post Edit screen > Theme Options > Sidebar. Here, you can choose the extra sidebar to display on your desired page / posts individually in the primary / secondary location.
Please write back to us if you have any further confusions.
Hope this Helps,
Best Regards !!