I don't see any option for Authentication settings under Admin Tab for SSO integration using SAML2.0, for a trial account.
This is a public discussion board for Canvas users from all over the world, so we don't really have any access to your account settings.
If you have a trial account, you may only have admin rights on a sub-account, or you may have only limited admin rights that do not allow you to set up custom authentication. You'll want to check with Canvas Support through the "Help" button after you've logged into Canvas.
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