How To Add 728×90 leaderboard Adsense ads between Header and Post Section in blogger

1.Log in to your dashboard--> layout- -> Edit HTML
2.Click on "Expand Widget Templates"
3.Scroll down to where you see this:

<b:section class='crosscol' id='crosscol' showaddelement='no'/>

4.Now replace above code with below code.

<b:section class='crosscol' id='crosscol' showaddelement='yes'/>

5.Now save your template.
6.Go to Layout > Page Elements
7.Now Click on new 'Add a Gadget' option that will now have appeared between Blog Posts and the Header.

8.Select 'HTML/Javascript' and add your 728x90 leaderboard Adsesne code and click save.
Now you are done.