Demo blocks can be disabled in Theme Options > Footer > Show footer demo blocks > Off.
Own content you can add to appropriate widget area (Appearance > Widgets).
I would recommend you to use static blocks to create content of footer and copyright blocks because static blocks can be edited using VC. To enable VC editor for static blocks go to wp-admin panel > Visual Composer > Role Manager > Post Types > Custom > tick “static block”.
Also, read our documentation http://www.8theme.com/demo/docs/royal/#!/9_footer and watch video tutorial – https://www.8theme.com/videos/ (Royal – WordPress ThemeEngine – Footer Set Up)
Let us know if you need any further assistance.