Let's get the obvious out of the way first – a vacuum is not a device that you push around to clean carpet. That's a vacuum cleaner. How they work will be explained later.
A vacuum is simply nothing. They can be small or very large (think outer space –it's nothing and it's huge!). Since a vacuum is nothing, it can't do anything. This is VERY important. When a the door of a space ship opens in a movie, the astronauts are NOT pulled out of the ship by the vacuum of space. There is nothing outside the ship to pull them out. (What actually happens is explained later.)
Make sure that you have wrapped your head around this idea. A vacuum is nothing and nothing can't do anything. In fact, the less air you have (the closer you get to a vacuum) the less that air can do.