Since Gmail isn't a TRL-specific product, I won't be writing directions on how to use it. What I will do is link you to some videos which I've found helpful on how to get the most out of Gmail.
We have many patrons asking for help with things that require email addresses. Many of these patrons do not have an email account or have had one in the past but do not know how email works. You can either direct them to this video or you yourself walk them through the process. This video is applicable to any popular email provider (Gmail, Yahoo, Outlook, etc.)