Help understanding Neural Networks please?

I posted this here, but thought you guys might be a good place to ask too!

I get the general theory of NNs - they're a rough model of our brain and work by passing input through the "input layer", to the hidden layers, computations are performed and one or more output neurons give us a result....

What I don't get is actually how it works in practice.

If someone could explain this to me really simply,or by using some kind of an example, I'd really appreciate it.

Or, imagine I have a game, and want to track a pattern in the game... ie. its a shooter game and I want to see if theres a correlation between different weapons and different levels and their success, could I use a neural network to recognise a pattern in this?

Thanks everyone!