We need advice on integration with Sberbank Equity

Who has experience connecting payments Sberbank Equivalent - need advice about the correct handling of callback after payment.

That is, after the payment is made, as I understand the site must send to the system a request with a secret key to get a reply that the order is really paid for.

We need advice

Upd. Heres the documentation https://securepayments.sberbank.ru/wiki/doku.php/integration:api:start