I have bought a reflection plate 5v1, so the video shows how the reflected light works:

I also bought white polypropylene sheet with tripods. I tried to light the background. The video shows also my mistake with camera position. Camera monitor did not reveal whole frame of shot, so that is the reason why we can see the edged of sheet. I have tried to light the figure from bottom to make more dramatic shot:

I have tried a green sheet to separate a green color by key effect and replace it by a picture. The key effect is not perfect because the light did not illumine whole sheet evenly. I have noticed here that the automatic white balance change the tone of skin in that shot, it is more orange (red) color here. I changed the color to be same as the background.

Here is the place where I build the scene (It is in my work).