How to make ajax call for auto suggest in Ninja Forms?

I have wordpress installed on one server and I am using Ninja Forms plugin to create a form. See the form here :- http://ift.tt/1SbfF9c

I want to add auto suggest in the Location, Airport fields. I know that I need to make ajax call using Javascript/Jquery once user start typing and get the results to suggest users.

But where do I add this javascript to make it work ? Can I do this via admin panel ? If not which file I need to look for ?

Thanks in advance for the help.

via Chebli Mohamed