An interesting transformation and a great one for you to do Izzie! Looks like it should be relatively easy to follow. One great thing about following that, and similar videos, is that you learn great post processing techniques for improving your own images!
Although I am not against doing limited forms of composite imagery, I try to stick with blending to images that I have taken at the same place and time to get the best I can out of what I have captured.
Mostly I try to improve the detail in the shadows and highlights and increase the DoF to what I see with my eyes when I look at a scene. It's a funny thing.
Folks that don't want to have fuzzy vision sometimes prefer fuzzy images (shallow DoF) which is not what they actually see but rather what is imposed by the shortcomings of the camera!
Admittedly, the Christmas Snow Globe and Photo Tree Ornament go beyond that point so I do slip off the fence on occasion, but I try to avoid the temptation to composite things like a jockey on a hummingbird.