Update docs/configuring-playbook-synapse-simple-antispam.md: add the section for installing

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-synapse-simple-antispam.md

@@ -1,6 +1,6 @@
 <!--
 SPDX-FileCopyrightText: 2019 Slavi Pantaleev
-SPDX-FileCopyrightText: 2024 Suguru Hirahara
+SPDX-FileCopyrightText: 2024 - 2025 Suguru Hirahara
 
 SPDX-License-Identifier: AGPL-3.0-or-later
 -->
@@ -24,3 +24,16 @@ matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeserve
 - example.com
 - example.net
 ```
+
+## Installing
+
+After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:
+
+<!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
+```sh
+ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
+```
+
+The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`
+
+`just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed. Note these shortcuts run the `ensure-matrix-users-created` tag too.