Hi yesaya handoyo,
In order to change RadScheduler's scaling, you can use the sample code below:
schedulerDayView.RangeFactor = ScaleRange.TenMinutes
I suggest that you also take a look at the RadScheduler control's samples in our Examples project, as there is a lot of sample code which will help you to learn how to use the control's features.
Please contact us again, if you have any additional questions.
the Telerik team