Set variable from copy data JSON output - correct syntax?

Hi!

I'm trying to create a pipeline that reads Power BI REST APIs and I would like to store the token I get in my first call in a variable to use it later in the authorization step for the next API call. But I'm having a hard time understanding what would be the correct syntax to get the value out from the first copy data that is in a JSON format. Any advice of the syntax or a link to documentation/tutorials how it should be build? 🙂 Or am I doing something completely wrong here? 😄 Thanks!