To set someone up with a Glass email address go into the icukhosting control panel
control.icukhosting.co.uk
(user and password should be in an email, i’m not including it here)
Add a new pop3 account
http://control.icukhosting.co.uk/pop3.cpl?AID=64461&action=add
Give the person an alias and a password.
Send instructions to their email with that username and password. Assuming they are using Gmail link them to the following document that explains how they have to set up their Gmail.
https://glassmagazine.wpengine.com/glass-emails/