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. From here, find the one you want to install, ensure the Install
Step 4: option is available in the dropdown and click the Submit button.
Step 5: The module will install and you will be taken to the main module page. The module should have an Installed status next to it. This means this payment processor option will now appear when checking out.