How to add Recent Posts Widget to Blogger

Step 1. Go to Template, click on the Edit HTML button

Step 2. Select the "Expand Widget Templates" box

Step 3. Search (using CTRL + F) for the following piece of code:

 ]]></b:skin>

Step 4. Just above this code, paste this one:

 /* Up and Down Buttons with jQuery
----------------------------------------------- */
.button_up{
padding:7px; /* Distance between the border and the icon */
background-color:white;
border:1px solid #CCC; /* Border Color */
position:fixed;
background: whiteurl(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijbs4ayn5IisAHkI68c7mEGdBvUgeKa-ZRuYVq9cLfHnCTdqkbXlbyfaqrKKy1XvbAAV1-AsNV2xqTdlEr9J1c4Um8CQaFc7sajmK49oSykQj6nSEMpJLT4nAhRc8t3S-ZtIGYsy7KaBE/s16/arrow_up.png) no-repeat top left;
background-position:50% 50%;
width:20px; /* Button's width */
height:20px; /* Button's height */
bottom:280px; /* Distance from the bottom */
right:5px; /* Change right to left if you want the buttons on the left */
white-space:nowrap;
cursor: pointer;
border-radius: 3px 3px 3px 3px;
opacity:0.7;
filter:progid:DXImageTransform.Microsoft.Alpha(opacity=70);
}
.button_down{
padding:7px; /* Distance between the border and the icon */
background-color:white;
border:1px solid #CCC; /* Border Color */
position:fixed;
background: white url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGWCTZ27xQhISfrVnuLKru4kIKkqlsnOc74XdlLMptaPvp-MF-DVdBk7wi7OyyTlRT-HQpfiX4lVJqgi2hgyBmOst7I_G9GAoMzXCpjXzau-4cWPz9ULJlcuaqOJmiDvTQR9Bud39NM9A/s16/arrow_down.png) no-repeat top left;
background-position:50% 50%;
width:20px; /* Button's width */
height:20px; /* Button's height */
bottom:242px; /* Distance from the bottom */
right:5px; /* Change right to left if you want the buttons on the left */
white-space:nowrap;
cursor: pointer;
border-radius: 3px 3px 3px 3px;
opacity:0.7;
filter:progid:DXImageTransform.Microsoft.Alpha(opacity=70);
}

Note:  - in green are some annotations that explains what styles you can modify on their left side.
           - You can change the arrows by changing the URLs in blue.
           - To change the buttons background color of buttons, change the white text with your color 

Step 5. Now search (CTRL + F) for this tag:

 </body>

Step 6. And just above it, paste the following code:

 <script src='http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' type='text/javascript'/>

<div class='button_up' id='button_up' style='display:none;'/>
<div class='button_down' id='button_down' style='display:none;'/>

<script>
//<![CDATA[
(function(){var special=jQuery.event.special,uid1='D'+(+new Date()),uid2='D'+(+new Date()+1);special.scrollstart={setup:function(){var timer,handler=function(evt){var _self=this,_args=arguments;if(timer){clearTimeout(timer)}else{evt.type='scrollstart';jQuery.event.handle.apply(_self,_args)}timer=setTimeout(function(){timer=null},special.scrollstop.latency)};jQuery(this).bind('scroll',handler).data(uid1,handler)},teardown:function(){jQuery(this).unbind('scroll',jQuery(this).data(uid1))}};special.scrollstop={latency:300,setup:function(){var timer,handler=function(evt){var _self=this,_args=arguments;if(timer){clearTimeout(timer)}timer=setTimeout(function(){timer=null;evt.type='scrollstop';jQuery.event.handle.apply(_self,_args)},special.scrollstop.latency)};jQuery(this).bind('scroll',handler).data(uid2,handler)},teardown:function(){jQuery(this).unbind('scroll',jQuery(this).data(uid2))}}})();

$(function() {
var $elem = $('body');
$('#button_up').fadeIn('slow');
$('#button_down').fadeIn('slow');
$(window).bind('scrollstart', function(){
$('#button_up,#button_down').stop().animate({'opacity':'0.2'});
});
$(window).bind('scrollstop', function(){
$('#button_up,#button_down').stop().animate({'opacity':'1'});
});
$('#button_down').click(
function (e) {
$('html, body').animate({scrollTop: $elem.height()}, 800);
} );
$('#button_up').click(
function (e) {
$('html, body').animate({scrollTop: '0px'}, 800);
} );});
//]]>
</script>

Note: In case you want to remove the "Go to top" button, remove the 1st bolded code and to remove the "Go to bottom" button, remove the 2nd one.

Step 7. Finally, Save your Template. Enjoy!