How to create new defect codes in Depot Repair setup

I would like to create defect codes. The documentation says the following:

1. Navigate to Defect Code Domains page using the following path:

   Depot Repair > Setup > Defect Code Domains

   The page lists all the existing Defect Codes.

2. Click Add Another Row to create a blank row to define the new defect codes.

3. Select the new Defect Code from the list of values.

It seems this setup step is really to create new Defect Code Domains for existing defect code values since the defect code must be selected from the list of values.

I cannot find any other documentation that addresses establishing the defect code values. Please tell me if you know. Thank you!