Confused about nose weights

Hi, I'm a total newbie to caravanning so feel free to be as basic as possible.

How do I know what the nose weight of my car is?  I've been reading through some threads and I see there is a gauge you can buy and you need to make sure the caravan is loaded in a certain way to get to the correct nose weight but I seem to be missing the key piece of information lol!

I think I need a begginers guide to caravanning!

Kerry