Adding .h5p activities programmatically to Drupal 8 nodes

I am using the H5P Drupal 8 module and am trying to inserting .h5p zip archives into newly created nodes through a script in a custom module.

I have tried to use the following code and am passing (to my knowledge) a complete $h5p_content array:

$H5PObj = H5PDrupal::getInstance();
$result = $H5PObj->insertContent($h5p_content, $contentMainId = NULL);

Am I missing something ? Do I need to call another function aside from insertContent()?

I identified three tables that seemed to be important for h5P activities: h5p_content, h5p_content_libraries, and node__field_[field_name]. node__field_[field_name] did not add a record after I called insertContent. And even if I entered the relational record in that table manually, it still did not load the H5P activity in the newly created node.

Am I missing a table ?