How do I add an email recipient so that my manager also receives the forms that our clients submit?

Nevermind I found it I think. :) 

Just in case you are still looking for the guide, here is how to have multiple recipients for a single notification:

https://www.jotform.com/help/39-Send-Notifications-to-Multiple-Recipients

You can also simply create a new notification and change the recipient:

https://www.jotform.com/help/25-Setting-Up-Email-Notifications