parts/nav-menu.html

@@ -0,0 +1 @@
+<!-- wp:navigation {"ref":104,"layout":{"type":"flex","orientation":"vertical","justifyContent":"right"}} /-->

theme.json

@@ -71,5 +71,11 @@
 			"background": "var(--wp--preset--color--background)",
 			"text": "var(--wp--preset--color--foreground)"
 		}
-	}
+	},
+	"templateParts": [
+		{
+			"name": "nav-menu",
+			"title": "Navigation"
+		}
+	]
 }