Where does one acquire the 'secret_code' using the POST /event/{id}/qr-codes endpoint for 'mint to wallet direct' flow?

We're looking to perform a mint directly to a wallet address using the following common flow: https://documentation.poap.tech/docs/popular-flow#4-minting-a-poap-directly-to-a-wallet.

For the first step, a 'secret_code' and event 'id' is required. The latter is acquired using the https://app.poap.xyz/admin/events create new POAP button after email response, but the former, the secret_code is in question.

Where does one acquire the 'secret_code' to process this common flow setup in minting POAPs directly to a wallet?

Thanks in advanced.