How I can import the groups via HTML file ?
Here is a YouTube tutorial how to import the groups. https://www.youtube.com/watch?v=Vr7QD9XvX18
You need to save the page only from this link https://www.facebook.com/bookmarks/groups/
Also you need have allow_url_fopen directive enabled on your server. You can try to contact your hosting support to enable it for you.