Determining What Content Gets Displayed

Question

I'm looking into using Wordpress as a basic content management system. I'm quite confused about what determines what content gets displayed when and where. For a simple example, I installed a theme and now I see something like this at the bottom of my "page": By admin on April 26, 2011 | Edit There's also a comment box down there and I didn't expect one to be there.

It appears that all I have to do is edit my page.php file to change this behavior but I'm a little baffled as to why the content delivery is so tightly coupled to the theme. I can make these changes now but if I decide to install a different theme I'm back at square one. It seems I should just be able to change a few settings to determine if I want those items (above) displayed when I create a "page".

I see there are many ways that content delivery is determined. Here's a quick list:

1. Settings within the Wordpress control panel. (Widgets, Menus, etc)
2. PHP code within your theme files.
3. Custom post types.
4. Plugins

So here's the question I've come to. Are there any simple rules or guidelines to help me determine what I might need to edit or customize when it comes to determining what gets displayed where?

Answer 1

The comment box will probably dissapear if you disable comments from the page editing screen (there's a checkbox).

To answer your question, no, there aren't any simple rules, but here's a rough outline:

Which posts are to be displayed is determined by the WP_Query class.

The way these posts are displayed, along with other elements is determined by the theme.

Plugins can modify anything.