Alerting docs: adds prereqs to configure data source (#96272)

* Alerting docs: adds prereqs to configure data source

* fixes numbering

docs/sources/alerting/alerting-rules/create-grafana-managed-rule.md

@@ -69,6 +69,12 @@ refs:
       destination: /docs/grafana/<GRAFANA_VERSION>/alerting/alerting-rules/link-alert-rules-to-panels/
     - pattern: /docs/grafana-cloud/
       destination: /docs/grafana-cloud/alerting-and-irm/alerting/alerting-rules/link-alert-rules-to-panels/
+  data-sources:
+    - pattern: /docs/grafana/
+      destination: /docs/grafana/<GRAFANA_VERSION>/datasources/
+  compatible-data-sources:
+    - pattern: /docs/grafana/
+      destination: /docs/grafana/GRAFANA_VERSION>/alerting/fundamentals/alert-rules/#supported-data-sources
 ---
 
 # Configure Grafana-managed alert rules
@@ -88,6 +94,13 @@ To make a backup of your configuration and to be able to restore deleted alertin
 
 ## Before you begin
 
+If you are using Grafana OSS:
+
+1. Configure your [data sources](ref:data-sources).
+1. Check which [data sources](ref:compatible-data-sources) are compatible with and supported by Grafana Alerting.
+
+If you are using Grafana OSS, Enterprise, or Cloud:
+
 You can use default or advanced options for Grafana-managed alert rule creation. The default options streamline rule creation with a cleaner header and a single query and condition. For more complex rules, use advanced options to add multiple queries and expressions.
 
 Default and advanced options are enabled by default for Grafana Cloud users and this feature is being rolled out progressively.