Under Faculty Services → Select Summary Class List
Select CRN and Submit
Select the Email class option at the bottom left of page and it will open your email program with the email addresses populated.
Copy those email addresses
Open Slack workspace and select workspace in upper left corner of screen → Invite people to workspace
Select the members option
Paste the emails that you copied from Banner into the field and add
The email addresses are populated to be sent as invitations → send invitations