1. Log in to blogger account >> Design >Edit HTML
2. Put check mark to "Expand Widgets Template"
3. Find this code, by using Ctrl+F
<div class='region-inner header-inner'>
4.you will find this code.
<div id='header-wrapper'>
<b:section class='header' id='header' maxwidgets='1' showaddelement='no'> 5. Replace the read value like this
<div id='header-wrapper'>
<b:section class='header' id='header' maxwidgets='3' showaddelement='yes'> 6. Click Preview and click save template.
7. After go to Page Element in Design tab
8.Click Add Gadget and select Adsense
9. Choose type you want.for example choose new linked 728x15 ad unit from the drop down
format menu for an Adsense ad that would sit above the blog title.and configure color.
10. Click save and view blog
