Hi,
Welcome to WordPress. There are two types of content that make up WordPress: Posts and Pages.
Posts are the blog-style posts that will be listed on your screen in reverse chronological order by default.
Pages are more for static content (such as detailed info about yourself and the site, or frequently asked questions etc.)
Posts can be categorised and tagged, pages can’t. Pages though can be arranged into parent and child pages as you referred to.
You will want to read through the following help file.
All of these can be administered from the same WordPress Admin panel you log into for your site. Click the Write tab and select Post or Page (to create a new one) or click the Manage tab and select Post or Page (to edit posts and pages you’ve already created).
Technically, everything shown on your site can be displayed using the index.php file but as you work more with WordPress and try out different themes, you’ll see there are different PHP files used for different types of content. For example, you can have a single.php file to style your posts and a page.php file to style your pages, placing different code in each to style the posts and pages differently from each other.
For now, if you want to style posts and pages exactly the same way, then depending on the theme you’re using having index.php will do this for you automatically.
Hope that helps.
Vaughan
