After theme activation you will see a top message box that advice you to install Revolution Slider. Follow the instruction for install and activate the plugin, after activation you will see a new menu voice: Revolution slider. If occur some error retry or go to Plugins page and activate the plugin manually.
You can import the slider of the demos by follow the instruction of Demo documentation.
Revolution slider is the most advanced slider for WordPress, there are so many options and you may need a guide. Go to Slider Documentation for more details.