Using graphql with cockpit

Can someone send me a tutorial in which I can see how to work with Cockpit by sending graphql queries ?

Did you check out this:

As you’ll see, it doesn’t support mutations but if you’re interested in only getting the data it should be a decent solution. Since it only provides GraphQL endpoint you might wanna use one of the desktop clients/IDEs to play around (e.g. GraphiQL desktop or GraphQL Playground)