Add documentation to clarify use of the Save mapping button

templates_qc/example_fov_grid_generate.ipynb

@@ -277,7 +277,13 @@
     "* Proposed tiles are drawn in red. Automatically-generated tiles are drawn in blue.\n",
     "* The selected proposed tile and its mapped automatically-generated tile are colored green.\n",
     "* The `Proposed tile` tab can be used to visualize current mappings to automatically-generated tiles.\n",
-    "* The `Automatically-generated tile` tab is used for re-mapping a tile created by this script to one of your's."
+    "* The `Automatically-generated tile` tab is used for re-mapping a tile created by this script to one of your's.\n",
+    "* When you're done generating your desired mapping, click the `Save mapping`. This will save your mapping to `mapping_path` specified earlier.\n",
+    "\n",
+    "Note:\n",
+    "\n",
+    "* The cells after this interactive widget (in the section `Use mapping to rename FOVs in tiled_regions_proposed`) are only to be run after you're satisfied with the mapping and clicked `Save mapping`.\n",
+    "* Prior to clicking `Save mapping` and re-running the cells in that section, ignore any error messages that may appear there."
    ]
   },
   {