How to implement new payment gateways

[component6]

Greetings! I have a question about the implementation of new payment gateways

For example: I created a class app/CustomPayPaymentGateway.php that implements the interface PaymentGateway

Where and how can I register a new gateway? I don't understand the line: PaymentGateways::register('paypal', PaypalPaymentGateway::class);