New page. Hidden page?

First and foremost, I have to say that I am still pretty new to WordPress, and very new to any kind of coding. So if you answer this, please answer as if I were dumb.

I have the Twilight Crown theme. I want to add a new page(s), however, I would like this page(s) hidden (to not show up on the header bar). I only want to be able to get to these pages from links in other pages.

Is this possible, and how would I begin to fathom such things?