explain how to use the replica

service/documentation.md

@@ -16,12 +16,29 @@ top-right of pages in the wiki here:
 
 <https://gitlab.torproject.org/tpo/tpa/team/-/wikis/>
 
-If not, you need to issue a merge request in the [wiki replica](https://gitlab.torproject.org/tpo/tpa/wiki-replica).
+If not, you need to issue a merge request in the [wiki replica][].
+
+[wiki replica]: https://gitlab.torproject.org/tpo/tpa/wiki-replica
+
+Because the wiki is actually mirrored to a git repository, it might be
+preferable to edit the Git repository and push there, so that the
+replica is up to date. See further instructions below.
 
 # How-to
 
 <!-- more in-depth procedure that may require interpretation -->
 
+## Editing the wiki through Git
+
+It is preferable to edit the wiki through the [wiki replica][]. This
+ensures both the replica and the wiki are in sync, as the replica is
+configured to mirror its changes to the wiki. (See the [GitLab
+documentation for how this was setup](howto/gitlab#accepting-merge-requests-on-wikis).)
+
+To make changes there, just clone and push to this git repository:
+
+    git clone git@gitlab.torproject.org:tpo/tpa/wiki-replica.git
+
 ## Pager playbook
 
 ### Wiki unavailable