Adding Pages
An excellent, professional website template should have more than one page layout included. Often the home (landing) page of the site has a special design, and may require its own layout. If that's the case, then internal pages - all the content pages of your site - might need a different, simpler layout.
If the home page is a "splash" page with a special graphic or animation that doesn't appear anywhere else, then clearly it requires a different structure to all the other pages.
You could get away with a template that has two page layouts - one for the home page, and one for all the internal (content) pages.
However, really good website templates will provide you with a number of layouts - a landing page, a general content page, a product catalog, a frequently asked questions page, and so on.
This gives you a great idea of how the template can be used to create a real-life website!
And it makes adding pages so much easier - simply chooses an existing page that matches the layout you want, click "Save, As..." and link the new page into your website.
Remember - a website template is a layout for your site - if the template has only one or two page layouts included, you will use those to create all the pages you need. Don't feel limited! Obviously, your job will be so much easier if you buy a template with a few different layouts!!
When adding pages to a website template, choose an existing page layout that closely matches what you want, save it under a new name, and build on that. Remember to link the new page back into your website navigation.