Custom Theme Issue…

Hi,

I am trying to create my own custom theme and I am at the very beginning. I have followed the following tutorial to get the pages in tact, and all went great:

https://themeshaper.com/2009/06/25/wordpress-theme-template-directory-structure-tutorial/

My problem is now I have installed a plugin, and I am not getting anything but a blank white page. I know the theme is correct cause if I right click and view source of the page, I see it’s the template (html code) I have just created, just that there are no plugins showing…Can someone tell me if there are some hooks I might be missing in the index.php page? I am thinking along those lines, but maybe I am going to far at first? Not sure please help!

Note: I have tried the plugin in the twentyfifteen theme and it DOES work, but not in my custom theme, it’s blank, other than the code from the above url I have followed.

Thank you
Brian