Set up customizable products in Commerce Manager

[GregTBD]

Most of our products are customizable.  For instance, we sells hats that have 3 fields of customization.  FB shop does not automatically offer customization, it requires some effort in Commerce Manager via a supplementary field.  Does anyone know it FB will support three custom text fields?  

The supplementary field spreadsheet I downloaded through Meta has only one column for a custom text field, I need three.

Is there an App for this?  Nothing jumped out at me.