You have seen how to integrate our Payment Wizard with your application using our secuconnect API. We have created a Payment Customer and a Smart Transaction, and started the Smart Trasnaction with payment method invoice. The last two steps could have been combined into one /start/invoice, but you have learned more doing it separately.
Furthermore you can:
use many more payment methods;
add a basket and shipping information;
reuse customer data and payment instruments;
cancel a transaction before or even after the payment is executed;
let our secuconnect SDKs assemble and parse requests and responses.
Some of the mentioned things are described in the Reference section below. If you don't find the needed information, please do not hesitate to ask us.