Display Block with Variables

Hi, I’m trying to add variables to my display datasource but I can’t get it to work.
What I’ve done is: Opened the authoring tool, selected a template and downloaded the code.
Then I imported it into voiceflow and tried to change a simple text into a variable (as shown in the video tutorial) but I keep getting an error.
Schermata 2020-02-20 alle 15.56.49
What should I do to get it to work?

enclose by double quotes. like this: