just copy paste this for a fixed back to top button at the bottom right
<a class="btn btn-primary" style="position:fixed; bottom:3px; right:5px; z-index:3;" href="#top">Back to top</a>
I could be thinking of something else, but I remember a while back that someone posted a "scroll back to top" button code! If anyone knows the code I'm talking about please link it to me!! :o