add info (#30701)

Author: maycmlee

layouts/shortcodes/observability_pipelines/source_settings/datadog_agent.en.md

@@ -1 +1,9 @@
-There are no settings to configure in this step.
+Optionally, toggle the switch to enable TLS. If you enable TLS, the following certificate and key files are required.
+   - `Server Certificate Path`: The path to the certificate file that has been signed by your Certificate Authority (CA) Root File in DER or PEM (X.509) format.
+   - `CA Certificate Path`: The path to the certificate file that is your Certificate Authority (CA) Root File in DER or PEM (X.509) format.
+   - `Private Key Path`: The path to the `.key` private key file that belongs to your Server Certificate Path in DER or PEM (PKCS#8) format.
+
+**Note**: All file paths are made relative to the configuration data directory, which is `/var/lib/observability-pipelines-worker/config/` by default. See [Advanced Configurations][10172] for more information. The file must be owned by the `observability-pipelines-worker group` and `observability-pipelines-worker` user, or at least readable by the group or user.
+
+[10172]: /observability_pipelines/advanced_configurations/
+<!-- 10172 link is used in multiple shortcodes, so if it is changed, make sure to update those shortcodes using find and replace -->