Great questions. Employees need a lot of training and guidance. Start with a google search for legal requirements in your state- definitely a HIPPA employee form and training in privacy practices and standards. Possibly an employee agreement outlining job duties, pay and status (i.e. employee at will).
After that work on customer service skills- managing patient flow in the office, phone calls, messages, payments etc.
The best thing to do is have an employee manual with each task written and explained. If you don’t have one yet have your employee make on as he/she learns the job.