Difficult modifications

[Gemshop]

I need to add a check box and a text field to the registation form

A Wholesale check box (for retailsers)

and a text field for them to enter thier Seller's Permit number or Buisness License number

and i need to store this information in the DB

 

I will later need to hide prices from retail customers and add & display extra Wholesale prices for the customers registers as Wholesale customers. I have been looking at create-account.php but i can't make sense of it. Anyone know a good place to look to figure out how to edit/read this?

 

Sorry if i'm posting in the wrong place.

Thanks.