How to use appRoleAssignment in Graph Api

I'm trying to leverage the beta api for assigning azure users to applications.

I looked at the documentation and tried a variety of attempts in a C# console app using HttpClient and WebClient and couldn't succeed. I then went to the Microsoft graph explorer https://developer.microsoft.com/en-us/graph/graph-explorer . I couldn't get it to work.

I looked at the documentation https://developer.microsoft.com/en-us/graph/docs/api-reference/beta/api/approleassignment_get

The document's actual documentation of the HTTP request which doesn't match the Example. The Graph Explorer seems to hint that the example is correct, but through various attempts, I can only get a response of

{
    "error": {
        "code": "Request_UnsupportedQuery",
        "message": "Direct queries to this resource type are not supported.",
        ...
    }
}

My essential url is https://graph.microsoft.com/beta/appRoleAssignments/

The example says {id} but I have no idea what to put in. I put in several guids, user ids, object ids, resource ids, and none worked.

It isn't saying any access denied messages so I assume it has nothing to do with Scopes (all though the documentation is a little empty regarding that as well).

Ideally, I'd be able to see if for a given Guest Azure User has access to a particular App, then I'd be able to go and Update the assignment. I'll probably also need to delete the assignment as well.