(You can also install a HTML template).
1.

You have to choose a XML Template
2.

Save the XML file on your hard disk.
3.

Go to your Blogger Control Panel - Edit HTML
4.

Browse the XML file you have saved and upload it.
5.
Finished!
« Home | Previous Post Title »
<ItemPage>
<p style="text-align:center">
« <a href="<$BlogURL$>">Home</a>
<span><BloggerPreviousItems> | <a href="<$BlogItemPermalinkURL$>"><$BlogPreviousItemTitle$></a> »</span><span style="display:none"></BloggerPreviousItems></span>
</p>
</ItemPage>
...
<b:skin><![CDATA[/*
-----------------------------------------------
Blogger Template Style
Name: Rounders
Designer: Douglas Bowman
URL: www.stopdesign.com
Date: 27 Feb 2004
Updated by: Blogger Team
----------------------------------------------- */
#navbar-iframe {
display: none !important;
}
/* Variable definitions
====================
<Variable name="mainBgColor" description="Main Background Color"
type="color" default="#fff" value="#ffffff">
<Variable name="mainTextColor" description="Text Color" type="color"
default="#333" value="#333333">
...