How do I add the employees if they do not have email addresses?
You are able to use the system if employees don't have emails!
The system requires that you add an email address as a mandatory field because this is the "login" for your user.
If they do not have an email, a suggestion would be that you create an email that represents them.
This can then be served as a user login.
For instance, if you have a John who works at your company, you can create a "fake" email called john@companyname.com, and this will serve as a login for him.
Hope that help1