button (calculated fields form) action

Hi,

I am new to wordpress, let alone PHP/Java or whatever common languages uses for web development.

AS the title, I am using calculated fields form plugin inside my web and I have a couples of input “number’ fields enter by user. However, I wanted to create a “button” when it is press, sample of inputs would automatically fill in these “number” fields for demo purpose.

Of the “button” parameters, I can only see the “OnClick event” is possible to get the action I need it to be done (I could be wrong) but don’t know how.

I have a little coding background but can’t seem to get any information from the internet that I can really understand with. Can someone please help me out here?

Thank you and appreciated.