There are a number of ways to do this with JavaScript. But I'm going to give you a solution that uses the new jQuery functionality in version 8. More specifically, I'm going to use the jQuery delay and fadeIn functions to manipulate the two HTML div tags that contain the progress bar and the previous and next buttons.
The code snippet below executes when the document is ready (when everything has been loaded onto the page). It then hides the div with the class name of "submit_div" and the div with the class name of "progress_bar" until the delay has been fulfilled. Then, as a bonus, I'm telling it to fade in the divs as a special effect. The value of the delay is 5000 or five seconds. The value of the fadeIn is 1000 or one second.
<script type="text/javascript">
$(document).ready(function(){
$("div.submit_div").slideUp(00).delay(5000).fadeIn(1000);
$("div.progress_bar").slideUp(00).delay(5000).fadeIn(1000);
});
</script>
Place this code into any of the Question Text boxes (Header 1, Header 2, Body, Footer) wherever you want it to work its magic. Of course you'll want to edit the delay to correspond with the length of your video. Just keep in mind that JavaScript uses milliseconds, so 1 second = 1000.