Call queues (attendance line, tech support, etc.)
If the user is new, add the user
Add the user as a presence to the lines you need to share
Click on Group Memberships
Click Add call queue membership
Search for the extension. Check the boxes that are appropriate to the user - are they a primary member, pickup member, etc. Click Add
If this is for a front office staff member, be sure to allow access to Voicemail and Notifications