Your described scenario is a bit brief, but can I assume you are in "Automations" (Admin >> Helpdesk Productivity)?

In the Actions you have selected "Send email to agent.

To add the ticket number click on the small green icon (bottom right) and select the applicable placeholder.

To add a cc, go to "Add new action" at the bottom, and select Add a CC.  See screen shot.

Is that what you are looking for?

I'm in Supervisor>Rules>Overdue_Tickets (rule I created)

Figured out the the placeholder insert but there's no option to add a CC on my version.

I believe I have it set-up correctly at this point but I don't understand the cadence of when it will send the email completely... 

The way I have it set (see screenshot) it will send email if Ticket is Overdue more than an hour, the Agent has not interacted with the ticket in 24 hours and the status is not Pending, Resolved or Closed.

How often will it send the email though? Once a day? 

The old "Dispatch'r", "Supervisor" and "Observer" rules are being replaced with the new "Automations", with three tabs within it (same as the previous three types of rules). They are available in all plans except Sprout. This is being rolled out slowly. I assume you can ask to get this enhancement early. The cc is obviously something new.

Basically the Supervisor rules will run every hour and process tickets that have been updated within the last 30 days. So I assume you will get 24 emails per day (assuming no action is taken). Maybe not ideal, especially outside business hours. Is it not possible to use the SLA options?

See also: What's changed in Automations