VideoPop Button Not There

I have uploaded VideoPop to the content file and activated the plugin. I have copied and pasted the provided code in the header.php just before </head>. I have uploaded a video in the admin panel. When I go to a page to post, the button that is supposed to say “Add VideoPop” is not there. Has anyone got any suggestions? If there is even a way to bypass the button situation and just create a page that would offer the link to the video file, that would be fine too.

Thanks for any help!