Location of default template file

Can you please tell me where the file is for the Default Template for Highend?

Here’s why:
We have added Forums to our site using bbPress and we want to have the sidebar display on all Forum pages. The Forum index page does display the Sidebar, but the rest of the Forum pages do not.

In the bbPress documentation one of the initial set-up steps is to “Make sure bbPress uses the page template we want”. And on my site, all the pages that have a sidebar are using the Default Template, so that’s the one I need to use.

Unfortunately, I cannot find any PHP file that is named Default, or any PHP file that indicates that it includes a Sidebar.

Here’s the forum index page (which is correctly displaying the Sidebar):
http://gamingdogs.com/forum/
But as you navigate deeper into the forums, the sidebar disappears, and we want to have one on all the forum pages. Here’s two examples:
http://gamingdogs.com/forums/forum/gamingdogs-com/
http://gamingdogs.com/forums/forum/gamingdogs-com/community-news/announcements/

Thanks for your time,
Patty