If you use a theme which does not allow you to insert HTML code the easiest way to embed flipgorilla in WordPress is to install the plugin
Just copy the embed code from your flipgorilla publication into a new snippet.
In the overview of the snippets you will then see the embed code which you can place anywhere on your site.
TIP: If you encounter problems with responsiveness if the snippet is placed in a column just delete the width definition in the style (as you see in the picture above, where there is only the height definition)