Iceberg: Emphasize setting REST catalog type and endpoint properties together (#1183)

Co-authored-by: Michele Cyran <michele@redpanda.com>

Author: 2 people

modules/manage/partials/iceberg/use-iceberg-catalogs.adoc

@@ -58,7 +58,14 @@ endif::[]
 To connect to a REST catalog, set the following cluster configuration properties:
 
 * config_ref:iceberg_catalog_type,true,properties/cluster-properties[`iceberg_catalog_type`]: `rest`
-* config_ref:iceberg_rest_catalog_endpoint,true,properties/cluster-properties[`iceberg_rest_catalog_endpoint`]: The endpoint URL for your Iceberg catalog, which you either manage directly, or is managed by an external catalog service.
+* config_ref:iceberg_rest_catalog_endpoint,true,properties/cluster-properties[`iceberg_rest_catalog_endpoint`]: The endpoint URL for your Iceberg catalog. You either manage this directly, or you have this managed by an external catalog service.
+
+NOTE: You must set `iceberg_rest_catalog_endpoint` at the same time that you set `iceberg_catalog_type` to `rest`.
+
+==== Configure authentication
+
+To authenticate with the REST catalog, set the following cluster properties:
+
 * config_ref:iceberg_rest_catalog_authentication_mode,true,properties/cluster-properties[`iceberg_rest_catalog_authentication_mode`]: The authentication mode to use for the REST catalog. Choose from `oauth2`, `bearer`, or `none` (default).
 ifdef::env-cloud[]
 +

modules/reference/pages/properties/cluster-properties.adoc

@@ -1898,6 +1898,8 @@ The frequency at which the Iceberg coordinator commits topic files to the catalo
 
 Iceberg catalog type that Redpanda will use to commit table metadata updates. Supported types: `rest`, `object_storage`.
 
+NOTE: You must set <<iceberg_rest_catalog_endpoint,`iceberg_rest_catalog_endpoint`>> at the same time that you set `iceberg_catalog_type` to `rest`.
+
 *Requires restart:* Yes
 
 *Visibility:* `user`
@@ -2176,6 +2178,8 @@ Path to certificate revocation list for `iceberg_rest_catalog_trust_file`.
 
 URL of Iceberg REST catalog endpoint.
 
+NOTE: If you set <<iceberg_catalog_type,`iceberg_catalog_type`>> to `rest`, you must also set this property at the same time.
+
 *Requires restart:* Yes
 
 *Visibility:* `user`