the key of perfect chroma effect
I'f you are asking yourself why doesn't your Photo Booth backdrop work as smoothly as showed its because the lighting conditions in your room. It is a bit uncomfortable putting together the adequate setting but you need a solid color background, like a blanket. Then, you need to illuminate evenly the background or blanket. This is the difficult part, you cannot let any shadow show nevertheless create a shadow just by walking in front of the background.
Pretty much you would need 3 lights, two key lights for the background (one on each side) and another fill light that is more softer just to give the shape of light to the person in front of the background.
Because you can't move the camera from out of the computer this tends to give a lot of trouble to do and if the light is strong enough it will make you sweat and if your thinking that a fan can solve that problem, well think again because the fan can cause the background to move and it will not work nicely if you have a moving background.
So, lighting conditions should be even all around the still and solid background and you should be fine.