The clip you provided is pretty low res to see clearly.
For the one at 0:09-0:14: It looks like they tried to combine two moving shots. Also looks like they had some trouble with a smooth transition in the motion so you can see where the shots change over. The whole clip has a blur effect on it while the 3d papers blow in the foreground. The blur helps blend the effect.
The second one at 0:24 looks like they just tried to line up the shots and faded between them.
You need to match your shot, lens, wardrobe and pose of everything you want to look like it’s not changing while you fade over. However if you’re shooting green screen, like they did, it will make it easier to fade the background layer while your foreground remains a whole clip.
There are varying degrees of complexity that you can reach with this effect ranging from easy to very difficult. Like most things, plan each transition carefully and you’ll save considerable time in post.
Hope this is what you meant by your question,
Mike Sevigny
TorusFX Inc.
https://www.torusfx.com
https://www.linkedin.com/pub/mike-sevigny/49/875/495