Registration
The registration flow is handled via the S2S API. You can find instructions on how to start the integration here .
Once you have access to the S2S API, you need to authenticate your requests. The authorization process is described here (requires sign-in).
After completing these steps, you can start registering new users.
The registration API is described here (requires sign-in).
Note
If the user is already registered, you can either ignore the ACCOUNT_ALREADY_REGISTERED error or prevent registering the same user again in the future.