Since we released v.20 of BeTheme, we introduced a new method of sliders installation. Now, when you install a pre-built website, the slider is imported automatically.
If you wish to install slider from a specific pre-built website you can do that easily. Just proceed like you would with installing a pre-built website but when the window presented in the screenshot below pops up, select the Selected data only > Revolution Slider demo and click Install button.