What's The Difference between all these Lens?

I'm new to all this Photography stuff.
I'm planning on getting a Nikon D3200, With the Lens… The 18-55mm one… I think.I'm not stupid, I just find all these different millimeters with all these different lenses confusing. Why are there different lenses? What does a 14-25mm lens do different than a Kit 18-55mm lens? What does that little F mean? What does 1.8 mean? What's the difference. Why do you need more than two lens? I don't really understand what it does differently. I'm getting this Camera MOSTLY for video shooting, So does the Lens Mostly matter for photos? Or does it do something to the videos as well?
Since i'm mostly getting a DSLR for Videos, What would you guys recommend? A Canon 600D or D3200? You guys can answer the camera Question last, please help me understand this whole lens thing.

You have asked a lot of questions that make it too long to answer in here, there's a limit to how many words we can answer each time.

Basically the lens differences are the distances they focus for. The bottom number is the close at the top is the furthest for the shot.

For example one of mine is 18-200 which means anything between those two distances will be in focus like its right in front of me. That lens is also called a telephoto lens.

The f stops and ISO numbers are adjustments to shutter speed and how much light you let in when you use it. The darker it is out the more light you need and you also need stability.

I suggest you also get yourself a tripod for night shots. When you get good with that equipment you can expand to special filters too.

Don't forget to always put a filter on all your lenses to protect them from scratches at minimum. They are the most expensive part to replace.