Exactly. You map the questions answers into Input set and then the values are available through Custom.
One has to check the json what exactly is required.
What I like too is that you can say which question/answer do you want to access exactly (inputs[x]).
Could you please provide more detail steps on how to get display value using build input set?
In build input set input you map the questions and answers.
then in next step you take output -> custom which gives you some strange string where at the end is .custom
instead of the .custom you will use inputs.displayValue (for display value of first question.
then  for the second etc....
I hope it helps.