Understanding Explain for Sharded Cluster: Enable Sharding Causing Error

When I follow the course into the “Understanding Explain for Sharded Cluster” chapter, I was able to get mtools installed, but when I ran

sh.enableSharding("m201")

I get the following response:

"MongoServerError: no such command: 'enableSharding'. Are you connected to mongos?"

What should I do from there?

Where you ran this command?
Please show a screenshot