I'm new to video scribe and I'm having problem with zooming out before blank(scribble out) page.Basically,the element before blank page zooming out and makes it smaller.

I tried uncheck zoom at end and clicked the set camera button but still the same. 

You need to select the scribble element, zoom the camera in and then click the set camera icon (with the element still selected).

The following articles and tutorials will help:

Setting the camera to create scenes

Use zoom and set the camera

VideoScribe tutorial 2 – Tuning your scribe