Adding the Shopify standard payment module
The Systempay payment module can be added in two ways:
The first method consists in adding the payment module via the Drupal_Commerce Back Office.
In the administration panel of your store, go to the Extension menu and click Install a new module.
Then click the Choose File button and load the payment module.
The second method consists in copying the module via FTP. To do this, copy the systempay commerce folder into the /modules folder if your website.