Help! How to Customise FLATPICKER?

As Ninja Forms has now moved to Flatpicker, there are a number of ways to customise it.

I’ve put javascript in <script> tags, in the same div as the form, but it stops the form displaying. I can’t even find the Flatpicker options file in the plugin.

1. How can I customise the date picker?
2. How do I initalise the config?
3. Where do I put the config?
e.g.

{
    minDate: "today",
    maxDate: new Date().fp_incr(14) // 14 days from now
}

There is a lot of information here:
https://flatpickr.js.org/getting-started/

I can see what I need to use, I just don’t know where the javascript goes.

Thank you.