hallo~~somebody help first step ~~ where can i find the file?

Please see This Guide which talks about that and is linked and mentioned just a tidbit before the first step which is assumed you already know how to do before Adding it to Facebook.

Then after that you will physically need to prepare it to be embedded which I think is more of what you might have been looking for actually and that is known as the " Embedding Code "

Please see this guide also:

http://www.jotform.com/help/34-Adding-a-Form-to-a-Web-Page