The Outlook add-in for Pipeline must be installed before proceeding. If you've not completed this step, see Outlook add-in - Installation.

After selecting an email in Outlook select the Datasite Add-in.
You are prompted to log in using the familiar Datasite login process. Click the menu in the upper right and select Logout to log out.
If you log in to Datasite with Multi-Factor Authentication click the pin icon in the Add-in before you open an authentication email. You need to maintain visibility of the dialog window where you put your one time code. Once you authenticate, you'll need to re-select your initial email.