If you're signing into a pre-existing Tettra account for the first time, you have two main options.
Follow the link in an email invite from your Administrator.
Go to https://app.tettra.co/
and use your Email address to sign in or authenticate through Google or Slack if your team has either integration connected.
Learn more about how to log in to Tettra using Slack and Google Single Sign-On here.
If you're unsure which method to choose, contact your Tettra Admin. Otherwise, you can authenticate through either option and change your sign in method from your settings later.