docs: add how to section (#823)

* docs: add how to section
- add how to section to docs with latest datetime search across multiple collections

* docs: update changelog

---------

Co-authored-by: Pete Gadomski <[email protected]>

Author: nlebovits

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Make `get_collection` raise if `collection_id` is empty ([#809](https://github.com/stac-utils/pystac-client/pull/809))
 
+### Documentation
+
+- Add "How to..." section to usage documentation with latest datetime search across multiple collections example ([#823](https://github.com/stac-utils/pystac-client/pull/823))
+
 ## [v0.9.0] - 2025-07-17
 
 ### Added

docs/usage.rst

@@ -555,3 +555,33 @@ example from **odc-stac**'s documentation:
 
 
 See each packages's respective documentation for more examples and tutorials.
+
+.. _how_to:
+
+How To
+++++++++++++
+
+Get the latest dataset across multiple collections
+-----------------------------------------
+
+When searching for multiple datasets across different collections, each dataset may be derived from a different time period. You may want to get the latest dataset for each collection instead of all available datasets.
+
+.. code-block:: python
+
+    from pystac_client import Client
+
+    client = Client.open("https://planetarycomputer.microsoft.com/api/stac/v1")
+    items = []
+    for collection in ["nasadem", "esa-worldcover", "jrc-gsw"]:
+        items.append(
+            next(
+                client.search(
+                    collections=[collection], max_items=1, sortby="-properties.datetime"
+                ).items()
+            )
+        )
+
+The result will be a list containing the most recent item from each collection:
+
+    >>> items
+    [<Item id=NASADEM_HGT_s56w072>, <Item id=ESA_WorldCover_10m_2021_v200_S60W030>, <Item id=90W_80Nv1_3_2020>]