You imported demo data with slider, but does not configured slider for your blog categories according theme documentation.
How to fix this in Revolution Slider 6.x (if you use older version - please update theme and all plugins to latest version first):
- Go to Revolution slider and edit your sample slider settings (BLOG_SLIDER slider).
- Edit slider settings and select posts categories that slider should use to fetch your posts:
- You can change any other settings as you wish (posts limit, sorting, etc).
- Save slider settings.