That utilizes the “Fixed” position setting on all objects. When an object is set to fixed, it sits on a plane in the viewable area for the user on whatever device they are using to view the content. It stays at the relative position it it placed in no matter when the user gazes during the scenario.
You can think of it as a “Heads Up Display”, where you can give the user information that should always be visible while they are progressing through their experience.
That example uses an Info Card. The text in the Info Card is:
%Questions Answered%/8 Questions Answered
There is a variable in the scenario called “Questions Answered” that I initialize to zero, and increment each time the user answers a question. The “%” nomenclature in the text is variable substitution, where whatever the value of the variable is gets updated in the text in real time.
The whole subject is covered here, for exactly that scenario: