Please note that this feature is available for annual Team plan users.
Once this feature is enabled in your space, You will be able to change the SSO Settings with this button:
You can fill in the 'Sign In URL' and 'Identity Provider Entity ID' fields.
This guide may be helpful with that: https://docs.helloid.com/hc/en-us/articles/115002885874-Configure-Google-G-Suite-as-a-SAML-IdP.
The "Login With ..." button text is only taking effect at that text at SpatialChat.
This will make it clearer for your guests that authorization is done through your Identity Provider.
How to allow guests to join your space with SSO enabled
You can enable/disable anonymous entrance in the Space Settings:
Please note that in that case, SSO settings will be temporarily disabled.