Can't see anything

Hi! How are you?

I'm in need for help. I'm trying to use H5P in Wordpress + Learndash... But, after installing the plugin, all I have is sadness and tears. Just kidding.

The problem is, when clicking to add a new content, the only thing that shows up on my screen is the message "Before you start", as a header for an empty page. Every other section works fine, just that does not show anything.

Any ideas about how can I solve that problem?

Thanks!