User Detail Purpose
User Details are the specific values contained within each of the identifier fields. For many use cases, users won't be given access to change these identifiers since they're automatically provided with an upload and on-going automatic updates. However, when using self registration, or if your company's profiles data is difficult to compile, it may be useful to have the users provide their own information.
Something for you to consider is when making the profiles identifiers editable, using profiles identifiers to allow for Event Access may cause issues. It may be best to open the challenge up to everyone & simply market to a target group.
Category Configuration
There are ten total categories (identifiers) available for your profiles. Each of these needs a title (the users will see this) a brief description is helpful and then all of the possible values for that identifier must be listed (there is no option for the user to data enter a value). Also, choose "yes" for user editable when asking the users to provide and / or update their own profile data.
Note that the choices presented to users will also include all other values currently in the system. For example, if a prior user upload contains values not in this list, they will be automatically added to the list presented to the employee.