The authentication tab contains settings associated with the authentication type choosen.

Authentication Tab
Select your authentication type from the drop down list.
When using Windows authentication, no further parameters are required. When using SAML2 authentication, more information is required, depending on the SAML2 provider you use.
Office 365 SAML2 authentication parameters example

Use the Azure AD / Extra ID button or Okta button to start the wizard to complete the required configuration. Once the wizard completes the following fields wil have been completed:
Copy and paste your identifier from you SAML2 provider. This might be called the Service Entity ID
Copy and paste your identifier from your SAML2 provider. This might be called the Provider Entity ID
Copy and paste the login URL of your SAML2 provider.
Copy and paste the logout URL from your SAML2 provider.
Copy and Paste the logout URL from your SAML2 provider.