Still not 100% clear on what you’re asking… I suggest you just try some schemas and mutations.
Try this URL in your browser: https://studio.apollographql.com/sandbox/explorer?endpoint=http://localhost:8080/graphql link
Or, if you’d prefer to not deal locally with Dgraph, open a free cloud instance at cloud.dgraph.io. The dashboard there allows one to interact with both DQL and GraphQL.