add multi-folder URL parameter note

Author: fedorov

notebooks/getting_started/part3_exploring_cohorts.ipynb

@@ -828,6 +828,17 @@
         }
       ]
     },
+    {
+      "cell_type": "markdown",
+      "source": [
+        "You can open multiple series by passing the list of bucket folders in the URL:\n",
+        "\n",
+        "https://volview.kitware.app/?urls=[s3://idc-open-data/262f1166-22e1-4eed-a2fe-c899e995640c,s3://idc-open-data/48a29c97-bb71-4f8f-b70b-688f36bca0c1]"
+      ],
+      "metadata": {
+        "id": "SSNXGczneqMw"
+      }
+    },
     {
       "cell_type": "markdown",
       "metadata": {