Revise the "Backporting merged changes" guide

Author: StanFromIreland

getting-started/git-boot-camp.rst

@@ -557,60 +557,80 @@ dismissing your previous review that requested changes.
 Note that pushing new changes after the auto-merge flow was enabled
 does **NOT** stop it.
 
+
 Backporting merged changes
 --------------------------
 
-A pull request may need to be backported into one of the maintenance branches
-after it has been accepted and merged into ``main``.  It is usually indicated
-by the label ``needs backport to X.Y`` on the pull request itself.
+After a pull request has been merged into ``main``, it may need to be backported
+to one or more maintenance branches. This is indicated by the
+:samp:`needs backport to {X.Y}` labels on the pull request.
 
-Use the utility script
-`cherry_picker.py <https://github.com/python/cherry-picker>`__
-to backport the commit.
+``miss-islington`` will automatically attempt to create backport PRs for the
+versions indicated by these labels. If ``miss-islington`` cannot create a
+backport PR due to conflicts, you can use the :pypi:`cherry-picker` tool to
+create the backport and resolve the conflicts manually.
 
-The commit hash for backporting is the squashed commit that was merged to
-the ``main`` branch.  On the merged pull request, scroll to the bottom of the
-page.  Find the event that says something like:
+You need the commit hash of the squashed commit that was merged into
+the ``main`` branch. ``miss-islington`` should post a comment when it is unable
+to create the backport automatically, including the full command and commit hash.
+If that comment is not posted, look for an event on the merged
+pull request similar to:
 
 .. code-block:: text
 
    <core_developer> merged commit <commit_sha1> into python:main <sometime> ago.
 
-By following the link to ``<commit_sha1>``, you will get the full commit hash.
+By following the link to ``<commit_sha1>``, you can get the full commit hash.
 
-Alternatively, the commit hash can also be obtained by the following Git
+Alternatively, the commit hash can also be obtained with the following Git
 commands::
 
    $ git fetch upstream
-   $ git rev-parse ":/gh-12345"
+   $ git rev-parse ":/gh-<PR number>"
+
+These commands print the hash of the commit whose message contains ``gh-<PR number>``.
+
+You can then use the commit hash and the :pypi:`cherry-picker` tool to create
+the backport. In the following command, ``<branch>`` is the target maintenance
+branch (for example, ``3.12``):
+
+.. code-block:: text
+
+   $ cherry_picker <commit_sha1> <branch>
 
-The above commands will print out the hash of the commit containing
-``"gh-12345"`` as part of the commit message.
+Then, follow the instructions provided. You will have to identify the files
+with conflicts, fix them, and build and run applicable tests if necessary.
+When you are finished, ``git add`` all modified files and run
+``cherry_picker --continue`` to push the backport.
 
-When formatting the commit message for a backport commit: leave the original
-one as is and delete the number of the backport pull request.
+The tool usually generates the commit message automatically. If it does not, use
+the following format: Keep the original commit message unchanged, except for
+removing the backport pull request number (``(#XXXXX)``). At the end of the
+message, append a ``(cherry picked from commit <commit_sha1>)`` line.
 
-✅ Example of good backport commit message:
+Example of good backport commit message:
 
 .. code-block:: text
    :class: good
 
-    gh-12345: Improve the spam module (GH-777)
+    gh-XXXXX: <original commit title> (GH-XXXXX)
 
-    * Add method A to the spam module
-    * Update the documentation of the spam module
+    <original commit body>
 
-    (cherry picked from commit 62adc55)
+    (cherry picked from commit <commit_sha1>)
 
-❌ Example of bad backport commit message:
+Example of bad backport commit message:
 
 .. code-block:: text
    :class: bad
 
-    gh-12345: Improve the spam module (GH-777) (#888)
+    gh-XXXXX: Custom title (GH-XXXXX) (#XXXXX)
+
+    * Custom message
+
+After the backport PR is opened, ``miss-islington`` will link it to the original
+PR and remove the corresponding backport label.
 
-    * Add method A to the spam module
-    * Update the documentation of the spam module
 
 Editing a pull request prior to merging
 ---------------------------------------