Hi Aston
I also had a similar requirement recently and through liferay community channels on slack I came to know that there is no official guide at the moment as its not ready yet. Also, at the moment its not possible to create a module (via Blade) based on form-field template because that too is also under progress. Check:
https://issues.liferay.com/browse/LPS-97844 and
https://issues.liferay.com/browse/LPS-98417 for more info.
Meanwhile, what I did to get this working was that I went through the sample module created by Renato Rego (available on:
https://github.com/natocesarrego/slider and made necessary changes in its code to create my own custom form field types. May be you should do the same for the time until LPS-98417 is fixed and available.
