how to fix structured data errors in blogger blogspot template

What is structure data?
Every Website or Blog important to have and fixing structure data based Markup using schema.org based in format like Micro Data and RDF recomended by Google you can place in html, Json script but google recomended use Json script codes to implement in template.
how to fix structured data errors in blogger blogspot template
You can add tag of listing Pages use Data Highlighter too for detail in snippets.
Google search engine will understand what markup on web contain inpormations within webpages e.g. if you have website about Car Company you must markup within web pages like about what kind of Cars, author, date, Specification of content, Price range and others important to listing in snipets search engines.
If you check and diagnose your blogsite use Structure data testing Tool Google for markup validation and find error and warning in structure data testing google lets fixed and update to make sure fixed any error. If you lookup your template blogger and testing diagnose with structure data testing Tool so you know error and warning notifications, its about blog id, post id, author, headline, image, Publisher, DateModified and MainEntityOfPage in Blog Posting, Blog Posting in blogger is Snipet for Deskop. Its big deal for Seo so search engunes know what structure data, the organize strured data is like by Google.
How to fixed error and warning in BlogPosting like that above, Step by step to change them use html markup :
- postid change <meta expr:content='data:post.id' itemprop='postId'/> and remove itemprop='postId'
- Blogid change   <meta expr:content='data:blog.blogId' itemprop='blogId'/> and remove itemprop='blogId'
- For Author or Publisher, adding it within blogposting
<b:if cond='data:blog.pageType != &quot;static_page&quot; and data:blog.pageType != &quot;item&quot;'>
<div class='postmeta'>
<h3 class='date-header'>
<span>Author: </span><b:include data='post' name='author-post'/>
</h3>
</div>
  </b:if>
<b:if cond='data:blog.pageType == &quot;static_page&quot;'>
<div class='postmeta'>
<h3 class='date-header'>
<span class='post-author vcard' itemprop='author' itemscope='itemscope' itemtype='http://schema.org/Person'>
<div class='foto'>
<amp-img alt='author-photo' class='authorphoto' height='80' itemprop='image' layout='responsive' src='G+ Photo Profile' title='author photo' width='80'/>
 </div>
<b:include data='post' name='author-post'/>
<meta content='G+ Photo Profile' itemprop='image'/>
</span>
</h3>
</div>
</b:if>
- Image warning replace bellow html below
<b:if cond='data:post.thumbnailUrl'>
            <meta expr:content='data:post.thumbnailUrl' itemprop='image_url'/>
          </b:if>
With
<b:if cond='data:post.firstImageUrl'>
<amp-img expr:src='data:post.firstImageUrl' height='160' layout='responsive' width='250'/>
<b:else/>
<amp-img expr:title='data:post.title' height='160' layout='responsive' src='Your Image mage.png' width='250'/>
            </b:if>
- DateModified
Add below code below
<span class='post-timestamp'>
                <b:if cond='data:top.showTimestamp'>
                  <data:top.timestampLabel/>
                  <b:if cond='data:post.url'>
                    <meta expr:content='data:post.url.canonical' itemprop='url'/>
                    <a class='timestamp-link' expr:href='data:post.url' rel='bookmark' title='permanent link'><abbr class='published' expr:title='data:post.timestampISO8601' itemprop='datePublished'><data:post.timestamp/></abbr></a>
                  </b:if>
                </b:if>
              </span>
Replace with below codes :
<span itemprop='dateModified'><a class='updated' expr:href='data:post.url' rel='bookmark' title='permanent link'><abbr class='updated' expr:title='data:post.timestampISO8601' itemprop='datePublished'><data:post.timestamp/></abbr></a></span>
- MainEntityOfPage
Find in your template
<article class='post hentry' itemprop='blogPost' itemscope='itemscope' itemtype='http://schema.org/BlogPosting'>
And replace with below code
<div itemType='https://schema.org/WebPage' itemprop='mainEntityOfPage' itemscope='itemscope'/>
And diagnose and check again test data in Structure data testing tool google.
Thanks.