Operating system: add steps on updating HA OS (#32320)

* Operating system: add steps on updating HA OS

* Fix markdown

* Update source/common-tasks/os.markdown

Co-authored-by: Stefan Agner <stefan@agner.ch>

---------

Co-authored-by: Stefan Agner <stefan@agner.ch>

source/_includes/common-tasks/update.md

@@ -1,8 +1,6 @@
-## Update
+Best practice for updating Home Assistant Core:
 
-Best practice for updating a Home Assistant installation:
-
-1. Backup your installation{% if page.installation == "os" or page.installation == "supervised" %}, using the backup functionality Home Assistant offers{% endif %}.
+1. Backup your installation{% if page.installation == "os" or page.installation == "supervised" %}, using the [backup functionality](/common-tasks/os/#backups) Home Assistant offers{% endif %}.
 2. Check the release notes for backward-incompatible changes on [Home Assistant release notes](/blog/categories/core/). Be sure to check all release notes between the version you are running and the one you are upgrading to. Use the search function in your browser (`CTRL + f` / `CMD + f`) and search for **Backward-incompatible changes**.
 {% if page.installation == "os" or page.installation == "supervised" %}
 3. Select **Create backup before updating** in case you encounter an issue that requires a rollback.

source/common-tasks/container.markdown

@@ -3,6 +3,9 @@ title: "Common tasks - Container"
 description: "Common tasks for Home Assistant Container"
 installation: container
 ---
+
+## Update
+
 {% include common-tasks/update.md %}
 {% include common-tasks/specific_version.md %}
 {% include common-tasks/beta_version.md %}

source/common-tasks/core.markdown

@@ -3,6 +3,9 @@ title: "Common tasks - Core"
 description: "Common tasks for Home Assistant Core"
 installation: core
 ---
+
+## Update
+
 {% include common-tasks/update.md %}
 {% include common-tasks/specific_version.md %}
 {% include common-tasks/beta_version.md %}

source/common-tasks/os.markdown

@@ -6,6 +6,50 @@ installation_name: "Operating System"
 ---
 This section will provide guides to some common tasks and information which you will need in order to run, maintain, and edit your Home Assistant OS system. For further details on any particular subject, make sure to refer to the documentation for specific add-ons or topics listed here.
 
+## Updating Home Assistant
+
+If you have the {% term "Home Assistant Operating System" %} installed, you receive update notifications from different components:
+
+- {% term "Home Assistant Operating System" %}
+- {% term "Home Assistant Supervisor" %}
+- {% term "Home Assistant Core" %}
+- Add-ons, if you have any installed
+
+### Updating the Home Assistant Operating System
+
+Updates of the {% term "Home Assistant Operating System" %} are independent of other updates. They do not trigger repair issues and are usually backward-compatible.
+
+#### Prerequisites
+
+- [Backup](/common-tasks/os/#backups) your installation.
+  - Make sure the backup is downloaded and stored outside of the system.
+  - So that you can restore from that backup in case there is an issue with the system.
+
+#### To update the Home Assistant Operating System
+
+{% tabbed_block %}
+
+- title: Using the UI
+  content: |
+
+    1. Open the **Settings** panel.
+    2. On the top you will be presented with an update notification.
+
+    _If you do not see that notification, in the top right, select the three dots menu and select **Check for updates**"._
+
+- title: Using the CLI
+  content: |
+
+    ```bash
+    ha os update
+    ```
+
+    _This updates to the latest version. If you want to update to a specific version instead, use  `ha os update --version 12.0`._
+
+{% endtabbed_block %}
+
+### Updating Home Assistant Core
+
 {% include common-tasks/update.md %}
 {% include common-tasks/specific_version.md %}
 {% include common-tasks/beta_version.md %}

source/common-tasks/supervised.markdown

@@ -4,6 +4,9 @@ description: "Common tasks for Home Assistant Supervised"
 installation: supervised
 installation_name: Supervised
 ---
+
+## Update
+
 {% include common-tasks/update.md %}
 {% include common-tasks/specific_version.md %}
 {% include common-tasks/beta_version.md %}