diff --git a/notebooks/tzis-tutorial.ipynb b/notebooks/tzis-tutorial.ipynb
index 125309b8ed0f55a69060fd9db1620125ef9594cf..e0c479d621cb9309c0b36b9afd506cc6d5c73099 100644
--- a/notebooks/tzis-tutorial.ipynb
+++ b/notebooks/tzis-tutorial.ipynb
@@ -384,6 +384,20 @@
    "metadata": {
     "tags": []
    },
+   "source": [
+    "## Parallelization\n",
+    "\n",
+    "Dask is used to parallelize the `write_zarr` function. Tzis tries to get a running client with dask's `get_client` function. If that fails, it opens a local client with half of the maximum available CPU and memory resources. \n",
+    "\n",
+    "Dask will process a default batch of 70 chunks at once. Most of the time, tzis resizes the batch so that it is most likely that the memory is not overloaded."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "4ec0cf68-ebb9-455a-b215-f58b4ff24a06",
+   "metadata": {
+    "tags": []
+   },
    "source": [
     "## Chunking - best practices\n",
     "\n",
@@ -617,7 +631,13 @@
     "xarry.open_zarr(zarrinput, consolidated=True, decode_times=True)\n",
     "```\n",
     "\n",
-    "This is possible if the container is *public*.\n",
+    "This is possible if the container is *public* (see *how to make a container public*).\n",
+    "\n",
+    "Tzis automatically generate an index file which contains URLs for all prefixes of the container. The location is \n",
+    "\n",
+    "```python\n",
+    "'/'.join([OS_STORAGE_URL,os_container,\"INDEX.csv\"])\n",
+    "```\n",
     "\n",
     "1. If your container is *private*, you have to use tokens and fsspec. If you create environment variables for OS_AUTH_TOKEN and OS_STORAGE_URL, you can get a fsspec mapper which than can be used for xarray:\n",
     "\n",
@@ -779,7 +799,7 @@
     "tzis.toggle_public(outstore)\n",
     "```\n",
     "\n",
-    "This will either make the container of the outstore *public* if it was not or it will make it *private* by removing all access control lists if it was public. Note that only container as a whole can be made public or private.\n",
+    "This will either make the container of the outstore *public* if it was not public or it will make it *private* by removing all access control lists if it was public. Note that only container as a whole can be made public or private.\n",
     "\n",
     "- With hand:\n",
     "\n",
diff --git a/tests/test_validations.ipynb b/tests/test_validations.ipynb
index 6abb290ce074719a524e93933091e427e501d0fb..cda0016e82c050befe432e9f88cb3708cd551aa3 100644
--- a/tests/test_validations.ipynb
+++ b/tests/test_validations.ipynb
@@ -58,7 +58,7 @@
     "\n",
     "def get_encoding(zarr_dset):\n",
     "    encoding = {var:zarr_dset[var].encoding \n",
-    "                for var in list(ds.variables.keys())}\n",
+    "                for var in list(zarr_dset.variables.keys())}\n",
     "    for var in zarr_dset.data_vars:\n",
     "        encoding[var].update(dict(zlib=True, complevel=1))\n",
     "    for var in zarr_dset.coords:\n",