add to docs: what if babs-check-setup fails

docs/source/babs-check-setup.rst

@@ -18,14 +18,58 @@ Command-Line Arguments
 Detailed description
 **********************
 
-`babs-check-setup` will perform these steps:
+--------------------------------------------------------------------
+What does ``babs-check-setup`` do?
+--------------------------------------------------------------------
+
+``babs-check-setup`` will perform these steps:
 
 1. Print out configurations of the BABS project;
 2. Perform sanity checks in this BABS project;
 3. Submit a test job to make sure necessary packages (e.g., `DataLad`)
    are installed in the designated environment. This happen when ``--job-test``
    is requested. We highly recommend doing so.
 
+---------------------------------------------------------------------------------------
+What if ``babs-check-setup`` fails or the BABS project's setup is not what I desire?
+---------------------------------------------------------------------------------------
+
+If running ``babs-check-setup`` (e.g., with test jobs) fails,
+or the summarized information from ``babs-check-setup`` is not what you desire,
+please remove the current BABS project, fix the problems, and generate a new BABS project.
+In details,
+
+#. Before removing the current BABS project, make sure you know what went wrong and what to fix.
+   Please carefully read the printed messages from failed ``babs-check-setup``.
+
+#. Remove the current BABS project
+   with following commands::
+
+    cd <project_root>/analysis    # replace `<project_root>` with the path to your BABS project
+
+    # Remove input dataset(s) one by one:
+    datalad remove -d inputs/data/<input_ds_name>   # replace `<input_ds_name>` with each input dataset's name
+    # repeat above step until all input datasets have been removed.
+    # if above command leads to "drop impossible" due to modified content, add `--reckless modification` at the end
+
+    git annex dead here
+    datalad push --to input
+    datalad push --to output
+
+    cd ..
+    pwd   # this prints `<project_root>`; you can copy it in case you forgot
+    cd ..   # outside of `<project_root>`
+    rm -rf <project_root>
+
+   If you don't remove the current BABS project, you cannot overwrite it by running ``babs-init`` again.
+
+   .. developer's note: above step: copied from `babs-init.rst` (CLI for ``babs-init``)
+
+#. Fix the problems, e.g., in the ``babs-init`` command,
+   or in the container configuration YAML file.
+
+#. Generate a new BABS project by running ``babs-init``.
+
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 Example commands
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