When you log into UMail's web interface in a browser, your mailbox is displayed. You can also open your team mailbox and other resources you have permissions for.
Log into www.umail.utah.edu.
In the upper right of the page, click on the icon for your account, and select “Open another mailbox…”
In the prompt that appears, enter the email address or search for the team or resource you want to access.
When you click “Open”, the mailbox will open in another tab.