Adding values for "On Condition" fields for required filter in Designer

I am looking for some information on how to add some more field values for "On Condition" to make a field required if the end user selects a certain field,

but cannot locate anywhere in the system to add more values/fields

so the end user would enter yes / no / N/A in the Added to IT Wiki field, if they select no or NA then the reason field becomes required.

this is in 9.1.5