How to implement the rule I asked

Summary:

I asked for a behavior rule in the Autocomplete Usecases. What is the next step?

Content (required):

Hi,

I asked for a behavior rule in the Autocomplete Usecases. The current status is Approved with limitation/workaround. What is the next step? How can I implement my request? Do I need to know how to write something in SQL?

This is the validation rule I asked for-

if the employee wants to add a phone that his type is not a work mobile phone, and the employee doesn't have a recode of a work mobile phone 

the system won't let him continue