There are a million ways to achieve great black and white from color video. The white background is a very well lit studio shoot. It may bee shot on a green screen stage but the effect is easier to pull off and looks better if you shoot in a studio with a white cyc. You can't match the look exactly without some real skill and plenty of good lighting equipment.
You get the black and white effect by using color correction tools or by going to the animation presets and choosing or searching for black and white. That's a good place to start.
Because of the question I think you are very new to AE. If so, please start here to get a handle on some of the basics.