Thanks for writing in! Are you using the Revolution Slider that comes with X theme? To activate the slider all you need to do is to navigate to Dashboard > Plugins > Revolution Slider and activate it.
Thanks for providing the screenshot. You are not required to activate or register Slider Revolution. We will be the one who will provide plugin updates through automatic updates which you need to validate X to have this feature. To know more how we utilize Slider Revolution in X, please check out our knowledge base here: https://community.theme.co/kb/integrated-plugins-revolution-slider#more-51511