Do I understand the creation of a manual money exchange site correctly?

Question

PHP

I received an order to make a site for manual money exchange. Will accept qiwi vouchers, alpha-bank, savings bank. Kiwi sber and alpha will also give. Do I understand correctly the principle of operation of a manual exchanger as follows. The client, let's say, wants to receive qiwi from alpha, on the site in the form he makes a transfer to me in alpha, I receive an SMS or email and I, in turn, from my qiwi wallet make him a transfer to his qiwi wallet. Same with everyone else. Is that how it's done?