[release-1.4] RHIDP-5373: Setting baseUrl (#884)

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modules/configuring/proc-provisioning-your-custom-configuration.adoc

@@ -21,7 +21,28 @@ It contains one secret per line in `KEY=value` form.
 . Author your custom `{my-app-config-file}` file.
 This is the main {product-short} configuration file.
 +
-You can start with an empty file to use the default configuration.
+The `baseUrl` field is mandatory in your `{my-app-config-file}` file to ensure proper functionality of {product-short}. You must specify the `baseUrl` in both the `app` and `backend` sections to avoid errors during initialization.
++
+.Configuring the `baseUrl` in `{my-app-config-file}`
+====
+[source,yaml,subs="+attributes,+quotes"]
+----
+app:
+  title: {product}
+  baseUrl: {my-product-url}
+
+backend:
+  auth:
+    externalAccess:
+      - type: legacy
+        options:
+          subject: legacy-default-config
+          secret: "${BACKEND_SECRET}"
+  baseUrl: {my-product-url}
+  cors:
+    origin: {my-product-url}
+----
+====
 +
 Optionally, enter your configuration such as: