Chapter 12.03: code does not work / error

Hi, the example code shown in this chapter does not work, Unity reports "SetDestination can only be called on an active agent that has been placed on a NavMesh". Can you please help?

By way of feedback this chapter is poorly explained as replicating the steps in the video does not let me get the same results, nor are the concepts clearly explained.

Thank you for your time. Sergio