STEP BY STEP
Step 1: Register an account
Register a payever account here: https://commerceos.payever.org/entry/registration/business
Step 2: Configure payment options
In order to configure your payment options, first click on Apps in the upper left corner and choose the Checkout icon. Alternatively, click on Open within the Checkout box on your dashboard.
Next, select the tab Payment options in the navigation bar at the top of the screen. Then click on + Add and choose the payment option(s) you want to implement from the list by clicking on Install.
The menu that opens after installing a specific payment option differs between the different payment options. For most payment options, you will be directed to the corresponding payment provider when you click on Connect. For the payment options powered by Santander (Factoring Invoice, Factoring Installments, Installments), you will be asked to enter the credentials that were provided to you from Santander, before clicking on Connect (if you have not been in touch with Santander before, please contact firstname.lastname@example.org).
Step 3: Configure channels
Select the tab Channels in the navigation bar at the top of the screen and click on + Add. From the list that opens afterwards, choose the shop system that you use for your online business and click on Install.
Select API keys and click on + Add. Enter a name of your choice and click on Generate. Afterwards, click on the plus icon (+) and you see the credentials that you have to insert into the shop system that you use for your online business (i.e., Client Id, Client secret, Business UUID).
Step 4: Install plugin
Search for the payever plugin in the Magento Marketplace and install it to your shop. Note that there are two different plugins for Magento 1 and Magento 2.
Step 5: Configurations
Log into your Magento backend and open the payever plugin settings (click on System in the navigation bar at the top, then click on Configuration and choose the settings for payever on the left side of the screen).
Fill in the API keys that you generated in your payever account (see Step 3) in the corresponding fields (Business UUID, Client Secret, Client ID) of the menu payever connection, set mode to 'live' and save these settings (by clicking on Save Config on the right). Next, synchronize the payment options with your payever account (by clicking on Synchronize in the Payment App).
After synchronization, check whether the payment options activated in your Magento backend are the same that are activated in your payever account and that you want to offer to your customers. By clicking on the arrow next to the payment methods, you can also change the individual settings for each payment option.
Before leaving these settings, make sure to save any changes by clicking on Save config.
Would you like to test the plugin and the payment options before you go live? No problem - you can do so in staging/sandbox mode, since none of the transactions will then result in an actual payment. To activate staging/sandbox mode, set mode to Sandbox in the plugin settings and click on Restore API keys to have the test credentials show up automatically. Alternatively, manually fill in the test credentials (Business UUID, Client secret, Client Id) provided here: https://docs.payever.org/resources/de/test-credentials
Note that you will neither be able to test with your actual credentials nor will you be able to live with the test credentials, so don't forget to manually fill in your actual credentials (Business UUID, Client secret, Client Id) again, once you are done with testing (otherwise you will get an error message).