Step 1: Log into your PrestaShop admin interface.
Step 2: Hover over the Modules tab in the upper menu bar and click on the Payment option.
Step 3: From here you will see all the modules, both installed and uninstalled, that are available.
Step 4: From here, find the one you want to install
Step 5: Ensure the Install option is available in the dropdown and click the Submit button.
Step 6: The module will install and you will be taken to the main module page.
Step 7: The module should have an Installed status next to it.
Step 8: This means this payment processor option will now appear when checking out.