--- a/doc/user_guide.txt	Fri Oct 08 00:37:16 2021 -0400
+++ b/doc/user_guide.txt	Thu Apr 21 16:54:17 2022 -0400
@@ -1,3 +1,8 @@
+.. meta::
+    :description language=en:
+        Describes how to interact with and use a tracker with the
+        Roundup Issue Tracker.
+
 ==========
 User Guide
 ==========
@@ -370,6 +375,24 @@
         @filters=status,keyword&
         @columns=title,status,fixer
 
+Full text search using the xapian, whoosh and native indexers treats
+the search query as a series of space separated words. Any word less
+than 2 characters or more than 50 characters is discarded. Also a
+stoplist is used to remove common words like "with", "and"
+etc. Additional stoplist words can be added in the tracker's
+config.ini file. Once filtering of the word list is done, each indexed
+item (e.g. title, file or message content ...) is searched and if all
+the terms are found in the item the item is returned. Then the items
+are mapped to an issue and the list of matching issues is generated.
+
+Other searching backends such as native-fts can be used in which case
+the filtering above is not used. The search query can support
+structure such as quoted phrases, matching one term or another rather
+than both (or search), prefixes etc. In this case you should look at
+the `documentation for configuring the native-fts`_ backend to find
+the supported format and features.
+
+.. _`documentation for configuring the native-fts`: admin_guide.html#configuring-native-fts-full-text-search
 
 Access Controls
 ---------------