If your Tettra account is connected to a Slack Workspace, you can connect your Slack user with your Tettra user. Doing so allows you to sign in with Slack and use Tettra's Slack integration features. This process also lets you convert an email user to a Slack user, (if, for instance, a new team member signs up for Tettra before logging into Slack for the first time.)
To connect your Slack user go to your 'My settings' page.
On the 'Integrations' tab you'll see a 'Connect to Slack' button.
Once you click the button you'll se the Slack authorization screen. If you're part of multiple Slack teams, make sure you choose the correct workspace - the Slack user you connect, must belong to the same to the connected Slack workspace.
After you 'authorize' Slack, you'll see the connected account on your integrations page: