I'm a wp newbie, so I'm not sure if I'm missing a basic

Hi, I'm a wp newbie, so I'm not sure if I'm missing a basic point.
I'm creating a site that has some wp generated pages & some static pages. I get that I can use Pages>Add New to create a static page. I've also managed to set up a theme, with the display that I'm after. However, when I use page.php from the theme folder, it doesn't show any of the content I have typed into the 'Add New' page section. I have read that I should create a new page in the theme folder called page-{slug} (in this case 'About') which I have done but it is still behaving in the same way as if I had just used page.php. Where am I going wrong?