Hi
You need to be very careful about altering the HTML of the form, as our plugin expects a certain structure, and if you alter this, it CAN break the functionality.
I do not have snippets I can share with you, you would need to hire a third party coder. But, you should not modify our core plugin files to do this. There is a great risk that an update would overwrite your edits.
V3 of our plugin (due in a few weeks, but I cannot say exactly when) allows a lot more flexibility when it comes to design changes.
If you are creating your own JS to do this, not that it may need to be loaded on document ready and also (possibly) on ajaxfinish and ajaxformfinish. These events are described here:
https://searchandfilter.com/documentation/faq/#will-my-lightbox-or-other-fancy-javascript-work-with-this-plugin