Edit prestashop module

I have a prestashop module that i need correct and finish, descripction:

- It is neccesary see a buttom in cart detail when a user want buy a product
- The buttom is a buttom amazon that must have a Amazon link where we selling the product that the user see in prestashop
- When user click the buttom prestashop must be know: Lenguage and location of the user
- This must be the lenguage and countries capables with the link: Spain -> ES, UK -> EN, USA -> EN, IT-> IT, FR -> FR, Nerthlands -> NL, Canada -> EN, Canada -> FR
- It is neccesary know the location and the lenguage because i need show a link for amazon.

Busissnes Ruls:

- In backoffice the admin must can configurate for each product the amazon link that must be appear in the buttom
- Must be appear amazon buttom only in the products that have configurated a link (previusly in backoffice)
- When user click in buttom must be redirect to amazon link deppending to country and lenguage (Look at Canada have two lenguages)

I have a part of module created but i need finish it.