This is how to set up a CDiscount seller account for AtomicSeller:

Store name: This is the full name of the store used only in user interface.
Store key: This is the main identifier of the store essential when using webservices.
Merchant key: This is the main identifier of the merchant (Optional except if you have multiple stores and multiple merchants)
User name: Provided by Cdiscount
Password: Provided by Cdiscount. This field is hidden for security reasons.
Token: Provided by Cdiscount
