You should check out this post which talks about how to auto fill fields without having to click on the auto fill button. 

If you require someone to manually click on the auto fill button, I would keep it simple and provide some instructions for the user, e.g. click on the auto fill button to populate the below table. If you make the fields in the table required, then the user will not be able to submit form until the data is populated.

Hope that helps!