How to use the @aws-cdk/aws-lambda.LayerVersion function in @aws-cdk/aws-lambda

visibilityTimeout: contentQueueTimeout,
    });

    const attributeQueueTimeout = cdk.Duration.seconds(30);
    this.attributeQueue = new sqs.Queue(this, "attributeQueue", {
      visibilityTimeout: attributeQueueTimeout,
    });

    // ----------------------------------------------------------------
    // Lambda Functions
    const baseEnvVars = {
      TASK_TOPIC: this.taskTopic.topicArn,
      REPORT_TOPIC: this.reportTopic.topicArn,
      CACHE_TABLE: this.cacheTable.tableName,
    };
    const nodeModulesLayer = new lambda.LayerVersion(this, "NodeModulesLayer", {
      code: lambda.AssetCode.fromAsset("????"),
      compatibleRuntimes: [lambda.Runtime.NODEJS_10_X],
    });
    this.recvAlert = new NodejsFunction(this, "recvAlert", {
      entry: path.join(__dirname, "lambda/recvAlert.js"),
      handler: "main",
      timeout: alertQueueTimeout,
      role: lambdaRole,
      events: [new SqsEventSource(this.alertQueue)],
      environment: Object.assign(baseEnvVars, {
        INSPECTOR_MACHINE: "",
        REVIEW_MACHINE: "",
      }),
    });

    this.submitContent = new NodejsFunction(this, "submitContent", {