Header goes over revolution slider video background
Possible Answers to Your Question:
1. Make sure you have Layers 1.2.12.
2. Go to the Customizer and expand the Header > Styling panel
3. Check off Sticky Header and Transparent Header
From there, it is up to Revolution Slider to know how to sit in the page. If it is forcing a margin, you must add custom styling to DevKit or the CSS panel (or the slide config) to remove any outside margins or to give it a negative margin that pulls it up to the top of the site. We are not able to test paid plugins, so I apologize for not being able to give you more exact advice. The revolution slider guys assure us the plugin is fully compatible with Layers, so you may be able to get their help with positioning.