Data From Entries – Number input rather than checkbox

Hi I am trying to recreate a form very similar to this: https://www.cravecupcakes.com/

I have a product form which I use to create products, I have used this link to figure out how to display all the information for a product together (hidden field made from combination of other fields),

I then use the data from entries field type on my order form. My problem is that instead of a checkbox or radio box for each entry I need a quantity field.

Is there some way I can hook into the code to do this? I’m comfortable with jumping into the PHP, just need a pointer of where to start.

Thanks