Adding payment modules
There are two ways of adding PayZen payment modules:
The first method consists in adding the payment module via the PrestaShop Back Office.
From the Back Office of your shop, in the module menu, select Add a new module and then select the zip file of the payment module.
Click on the Upload the module button.
The second method consists in copying the module via FTP. To do this, copy the Payzen folder from the module archive into the modules folder of your website.