Handle the creation process for a wizard form

I've created a form with a Wizard but it doesn't 100% reflect the structure of my DB. For example, I have a fairly complex repeater for creating products, and I'd like to store the field values in a Json in my “products” table. Where I'm stuck is that I have no idea how to intercept the form's submit in order to process the data myself and insert it into my DB.

So I created a submit action button using this method: https://filamentphp.com/docs/3.x/forms/layout/wizard#rendering-a-submit-button-on-the-last-step

And then what do I do to process the submit?

I found this: https://filamentphp.com/docs/3.x/panels/resources/creating-records#customizing-the-creation-process in the documentation.

I've added the method to my resource file, but it doesn't seem to be called when I click on the "submit" button.

Is there a particular method to use when on a Wizard? I can't find much
Thanks in advance