You will have to sign into your adsense account and make sure you insert password and username correctly.
Then on your adsense account page you will have to create an ad unit just click on My ads >>> and click New ad unit. And when doing this make sure you have a good internet network to make things more easier for you.
Now create a description for your new ads and then choose link ad it is located below ad siz and click on 200×90 vertical extra large ( x-large ).
Now make it look the way you want it to be like and then click on the save button.
Then copy the codes being given to you.
Now click here to parse your code and copy your parse codes.
Now create a new tab on your desktop go to your blogger dashboard.
Scroll down and then click on template and then click on the gear button below the mobile.
Select custom from the drop down menu and click save. Check out the image below.
Now still on that template click on edit HTML and then on your blog HTML code click on CTRL + F on your keyboard to enable search for this code below.
<b:includable id=’post’ var=’post’>
<div class=’post-body entry-content’ expr:id=’"post-body-" + data:post.id’ itemprop=’articleBody’> <data:post.body/>