MongoDB,如何将对象插入到新集合中?

I have a return object coming from instagram. I am trying to skate the entire build DB table structure process, I understand Mongo is the ideal DB to use for this task.

I am using the regular instagram libraries https://github.com/cosenary/Instagram-PHP-API and my test code runs without error. I don have the PhP PECL mongo libraries installed, I should be good to go.

session_start();
require 'vendor/autoload.php';
use MetzWeb\Instagram\Instagram;
$instagram = new Instagram(array(
  'apiKey'      => 'xxx',
  'apiSecret'   => 'xxx',
  'apiCallback' => 'http://103.238.173.97/success.php'
  ));

$accessToken = $instagram->getAccessToken();
$_SESSION['InstagramAccessToken'] = $accessToken;
$instagram->setAccessToken($_SESSION['InstagramAccessToken']);
$popular = $instagram->getPopularMedia();
// After getting the response, let's iterate the payload
var_dump($popular);

added just now:

$conn = new MongoClient('mongodb://localhost/?w=1');

$db = $conn->instagram;

// access collection
$collection = $db->instagram1;
$collection->insert($popular);

How would I construct a PDO query to 'autobuild' the table structure just like the JSON object at reply from my request?

instagram JSON object

Repaste of object. Most got cut off due to size

Update: I tried to insert straight into a collection, I get no error but the DB is still the same size

show dbs Data 0.078GB admin (empty) instagram 0.078GB local 0.078GB test 0.078GB week1 (empty)