Help understanding codeigniter MVC

I am trying to build my first codeigniter app, but not understanding how things should link up.  I read the documentation and it is not clear.

Here is what I want to do.  I have a form in my view that collects data, I want to send the data to the model to insert it into my database.

To do this, what would a simple model view and controller example look like?  Also any suggestions on how to learn CI faster would be appreciated.

Thanks,  Tom Ashworth