[Backport 2.6] Add steps for upgrading OpenSearch with Security enabled

_install-and-configure/upgrade-opensearch/appendix/index.md

@@ -0,0 +1,21 @@
+---
+layout: default
+title: Upgrades appendix
+parent: Upgrading OpenSearch
+has_children: true
+nav_order: 30
+redirect_from:
+  - /upgrade-opensearch/appendix/
+---
+
+# Upgrades appendix
+
+Use the upgrades appendix to find additional supporting documentation, such as labs that include example API requests and configuration files to supplement the related process documentation. Specific procedures outlined in the appendix section can be used in a variety of ways:
+
+- New OpenSearch users can use the steps and example resources we provide to learn about configuring and using OpenSearch and OpenSearch Dashboards.
+- System administrators who work with OpenSearch clusters can use the examples we provide to simulate cluster maintenance in a test environment before applying any changes to a production workload.
+
+If you would like to request a specific topic, please comment on issue [#2830](https://github.com/opensearch-project/documentation-website/issues/2830) in the [OpenSearch Project](https://github.com/opensearch-project) on GitHub.
+
+The specific commands included in this appendix serve as examples of interacting with the OpenSearch API, and the underlying host, in order to demonstrate the steps described in the related upgrade process documents. The intention is not to be overly prescriptive but instead to add context for users who are new to OpenSearch and want to see practical examples.
+{:.note}