To change the slider you have to disable the slider first from the page meta option & then use any of your choosen slider plugin like revolution slider or layer slider to make your video slider & use it in the vc option that’ll be all.

Can you tell me the steps for that please ?? also how to use the revolution slider on the same place ? also please if you have a preferred or recommended (video&Images) slider can work smoothly with the theme i will be so thankful..