This is one of cool trick for blogger to create a smooth scroll to top. If you have lot of content on you blog pages, and if you want to make your blog to be easy to navigate for your readers, a back to top button will make it easy and perfect.and also see this post it is important stylish back to top button
1) Go to your dashboard click on template and then edit html

2) click on proceed
3) click on expand widget template
4) use Ctrl+F and find </body>
5) Paste the given codes just before it </body>

<a href='#' style='position: fixed; bottom:5px;left:5px;' title='Back to Top'><imgsrc='http://a.dryicons.com/images/icon_sets/coquette_part_5_icons_set/png/64x64/blue_arrow_up.png' style='border: none;'/></a>

6) click on save template and your setting have been save

you can change the arrow with red colour with your own choice here some arrow and there URL copy the URL of arrow uoy want and relace it with red colour URL

                                                     LIST OF BACK TO TOP BUTTON
http://3.bp.blogspot.com/-d0-uQHmmbF8/UVO6yXg4mCI/AAAAAAAAAO0/9O196WOXygo/s1600/1uparrow.png
 http://2.bp.blogspot.com/-vGbwSmxJMQw/UVO6yZ9_HaI/AAAAAAAAAOw/uyiPk3oapao/s1600/Up%2520Arrows%2520Icon.jpg
http://4.bp.blogspot.com/-R4phcepz7_E/UVO6ySlgjDI/AAAAAAAAAO4/4VNGfG8G3KY/s1600/Up%2520Icon.jpg
http://2.bp.blogspot.com/-IUXHqKX-b0E/UVO8GZOU9aI/AAAAAAAAAPQ/Zi5U2PbYUc8/s1600/Back_to_top_image.png
http://2.bp.blogspot.com/-POSUvFqfb-c/UVO8GgM1QPI/AAAAAAAAAPY/SOVnkGLCOEI/s1600/back+to+top.png
http://1.bp.blogspot.com/-JN2h0GeHWxk/UVO8HhTFgiI/AAAAAAAAAPo/mmcD3HaDMTY/s1600/back_to_top_button.png
http://4.bp.blogspot.com/-hR0EZFB1Iu0/UVO8HukwnqI/AAAAAAAAAPw/z0BjjeW56tY/s1600/back+to+top+icon.png
 http://4.bp.blogspot.com/-EzI8BGPJeng/UVO8IxUttFI/AAAAAAAAAQA/RAahnPe--Tw/s1600/rb+back+to+top+11.png
 http://1.bp.blogspot.com/-nQMG0MdTCCw/UVO8MQnIwCI/AAAAAAAAAQ4/hKB3EP01sp8/s1600/rb+back+to+top+9.png