JSON-LD Playground:

frame.jsonld

{
  "@type": "http://example.org/vocab#Library"
}

markup.jsonld

{
  "@context": {
    "dc": "http://purl.org/dc/elements/1.1/",
    "ex": "http://example.org/vocab#",
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "ex:contains": {
      "@type": "@id"
    }
  },
  "@graph": [
    {
      "@id": "http://example.org/library",
      "@type": "ex:Library",
      "ex:contains": "http://example.org/library/the-republic"
    },
    {
      "@id": "http://example.org/library/the-republic",
      "@type": "ex:Book",
      "dc:creator": "Plato",
      "dc:title": "The Republic",
      "ex:contains": "http://example.org/library/the-republic#introduction"
    },
    {
      "@id": "http://example.org/library/the-republic#introduction",
      "@type": "ex:Chapter",
      "dc:description": "An introductory chapter on The Republic.",
      "dc:title": "The Introduction"
    }
  ]
}

playground.jsonld

{
  "@context": {
    "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
    "playground": "http://json-ld.org/playground#",
    "description": "rdfs:label",
    "startTab": "playground:startTab",
    "copyContext": "playground:copyContext",
    "markup": {
      "@id": "playground:markup",
      "@type": "@id"
    },
    "context": {
      "@id": "playground:context",
      "@type": "@id"
    },
    "frame": {
      "@id": "playground:frame",
      "@type": "@id"
    }
  },
  "description": "",
  "startTab": "tab-framed",
  "copyContext": false,
  "markup": "./markup.jsonld",
  "frame": "./frame.jsonld"
}