1. For the header, please try to go to Customize > JNews : Header Option > Header – Desktop Option > Desktop Header Width then choose the Fullwidth option.
2. For the Overlay slider, Please make sure if you have been using Landing Page template on that page. For more detail about Landing Page template, please visit our documentation right here http://support.jegtheme.com/documentation/page/ and jump into Landing Page Template section. Also, please use a separate row (single row) for the overlay slider.