add note for installing the cli extension (#30593)

Co-authored-by: hubwriter <[email protected]>

Author: nquinlan

content/copilot/github-copilot-in-the-cli/enabling-github-copilot-in-the-cli.md

@@ -17,6 +17,12 @@ shortTitle: Enabling Copilot in the CLI
 
 The {% data variables.product.prodname_copilot_cli %} public beta is available to all organizations{% ifversion ghec %} and enterprises{% endif %} that have an active {% data variables.product.prodname_copilot_for_business %} license. You can enable or disable {% data variables.product.prodname_copilot_cli_short %} for your organization{% ifversion ghec %} or enterprise{% endif %} in the {% data variables.product.prodname_copilot_short %} settings.
 
+{% note %}
+
+**Note:** To use {% data variables.product.prodname_copilot_cli %}, after it has been enabled, users must install the {% data variables.product.prodname_copilot_cli %} extension, see "[AUTOTITLE](/copilot/github-copilot-in-the-cli/using-github-copilot-in-the-cli)."
+
+{% endnote %}
+
 ## Enabling or disabling {% data variables.product.prodname_copilot_cli_short %} at the organization level
 
 An organization owner can enable or disable {% data variables.product.prodname_copilot_cli_short %} for the organization. {% ifversion ghec %}You may not be able to configure this setting for your organization, if an enterprise owner has set a policy at the enterprise level.{% endif %}