GrapesJs and PHP - store and load data to show in editor and as HTML page as well

I am using GrapesJS to build a simple webpage.

I included the script in the following way inside head part :

<script type="text/javascript" src="js/jquery-1.10.2.js"></script>
<link rel="stylesheet" type="text/css" href="grapesjs-dev/dist/css/grapes.min.css">
<script type="text/javascript" src="grapesjs-dev/dist/grapes.min.js"></script>

I am using GrapesJS to build a simple webpage.

I included the script in the following way inside head part :

<script type="text/javascript" src="js/jquery-1.10.2.js"></script> <link rel="stylesheet" type="text/css" href="grapesjs-dev/dist/css/grapes.min.css"> <script type="text/javascript" src="grapesjs-dev/dist/grapes.min.js"></script>

HTML:

<div id="gjs" style="height:0px; overflow:hidden;">
</div>

Javascript :

<script>      
       var editor = grapesjs.init({
        showOffsets: 1,
        noticeOnUnload: 0,
        container: '#gjs',

        fromElement: true,

        height: '100%',
        fromElement: true,
        storageManager: { autoload: 0 },


   assetManager: {

     assets: [
     'http://placehold.it/350x250/78c5d6/fff/image1.jpg',
     // Pass an object with your properties
     {
       type: 'image',
       src: 'http://placehold.it/350x250/459ba8/fff/image2.jpg',
       height: 350,
       width: 250
     },
     {
       // As the 'image' is the base type of assets, omitting it will
       // be set as `image` by default
       src: 'http://placehold.it/350x250/79c267/fff/image3.jpg',
       height: 350,
       width: 250
     },
    ],

  },


   storageManager: {
    type: 'remote',
    stepsBeforeSave: 1,
    autosave: true,         // Store data automatically
    autoload: true,
    urlStore: 'save_now.php',
    urlLoad: 'load_now.php',
    // ContentType: 'application/json',
    // For custom parameters/headers on requests
    //params: { _some_token: '....' },
    contentTypeJson: true,
      storeComponents: true,
    storeStyles: true,
    storeHtml: true,
    storeCss: true,
     headers: {
    'Content-Type': 'application/json'
    },
    json_encode:{
    "gjs-html": [],
    "gjs-css": [],
    }
  //headers: { Authorization: 'Basic ...' },
  }


      });

 window.editor= editor;




var blockManager = editor.BlockManager;

// 'my-first-block' is the ID of the block
blockManager.add('my-first-block', {
  label: 'Simple block',
  content: '<div class="my-block">This is a simple block</div>',
});


 </script>

So I get in the blocks panel a block namely Simple block which I can drag and drop on the editor. When ever any change is made then the autosave is trigerred with an ajax call to save.php file. Inside save.php, I have:

$content_found="";
$content_found= file_get_contents('php://input');

mysqli_real_escape_string($conn, $content_found);
echo " content found = ".$content_found;
$sql = "INSERT INTO `grapes_content` (`content_found`)
VALUES ('".$content_found."')";

But in Chrome developer tool network tab, I can see :

It is not clear what payload variables I should save in database and how . I used $content_found= file_get_contents('php://input'); to get the full content instead.

After saving it into DB, on page refresh, I load the page with load_now.php. Inside load_now.php, I have 👍

$content_found="";
$sql = "SELECT * FROM  `grapes_content`";
$result=$conn->query($sql);
$content_found="";
while($row=mysqli_fetch_assoc($result)){

    $content_found=$row['content_found'];

}

echo $content_found;

But the editor shows no saved data.

I am pretty sure that the way I save and retrieve data is not correct. So points are:

Q1) What things should I save in database ? And how can I get the variables or data from ajax payload or in any other way ?

Q2) How can I show the saved data into the editor after page reload ?

In the editor, I see a preview option with an eye image that can show me the HTML page without any editor.

Q3) After saving data into database, how can I show the data simply just as a HTML page and not inside any editor ?