In my understanding, you cannot simply paste the code to the ‘Custom Code’, because you have to replace the parameters like order totals, who buy it, and who refer the customer.
If you want a no-code solution for Wix Store, at this moment, we found Tapffilate (Google it). They provide a premade code so you don’t need to think anything.
If you want to stay on your platform, please use Wix Fetch and Store Backend Events (so the ‘send’ is triggered)