I just recently downloaded and started using Ubuntu 12.04 LTS and this is my first Linux/unix OS ever. I've been faced with a gigantic learning curve that I think would deter most people.

With that in mind, is there a free "Ubuntu for dummies" type website/article/guide somewhere?

I mean, something that would even be as simple as to describe the difference between the windows file storage tabulation (C:Windows...etc) vs Linux tabulation (etc/default/... etc etc etc).

I am often researching things on how to improve / fix my Ubuntu and am rapidly confused because the help forums make basic assumptions about ideas like this. I don't necessarily already know where the "etc" folder is. I didn't even know what Nautilus was even though I had already been using it.
These are my problems.

Is there such a guide? One which will be simple, and easy to understand? One which will be free of charge?