A great way of creating a smooth transition from one scene to the next, is to add a fade out from one scene and fade in to the next.
This is easy to achieve in the Hololink editor, by checking the Use transition box below the object behavior, when choosing Change Scene.
1 - Choose Behavior - Change Scene and the Target Scene.
2 - Check the Box and choose Fade to color or Fade to image.
3 - Set the Fade out and Fade in time (in seconds).
4 - Choose the colour that you want to fade to and from.
OR
5 - Choose the image you want to fade in and out from
Now your scenes will fade out and in. Go ahead and try it for yourself.