I am using dynamic content gallery plugin, and i have to add a php code directly to the home page for it to show.
I am merely curious on which php file modify the home page since there is no home.php? Help would be greatly appreciated.
There is no home.php, the index.php handles the front page. However, the best method to accomplish what you want is to add your shortcode on a php widget then place that on any of the many widget areas available for Frontier (Post – Header, Post – Before Content, etc…) You can then use widget logic ( is_front_page() ) so that the widget only appears on the home page.
Examples of Widget Logic usage