Configuring Mattermost Operator deployment (PostgreSQL DB)

Summary
I have installed a test instance of Mattermost using the Kubernetes operator. I also created a PostgreSQL StatefulSet deployment and provided the credentials to my Mattermost operator deployment. Mattermost is deployed and accessible. I have also verified that the mattermost instance was able to connect to the database and create tables etc.

My question is how do I edit the initial configuration of Mattermost so I can at least login via admin account? Also, is it possible to configure features like SSO/SAML and my organization during operator deployment (i.e. using a k8s configMap, secret etc).

I see that there is a .go file that sets MM_CONFIG to DB_CONNECTION_STRING so I figure I need to set that somewhere like so:
https://docs.mattermost.com/configure/configuation-in-mattermost-database.html

But I’m still at a loss as to how I create the initial admin user, let alone all of the other configs like SSO etc. Thank you for any help!

EDIT: I did try accessing one of the pods from my deployment and running:

mmctl user create --email test@domain.com --username admin --password apassword

This gave me:

Error: cannot read user credentials, maybe you need to login firse: stat /.config/mmctl/config: no such file or directory