Update VR Controls Design

VR-Controls-Design.md

@@ -5,6 +5,8 @@ In short, set the centrepoint of the scene with
 with a **child** [`XRCamera3D`](https://docs.godotengine.org/en/stable/classes/class_xrcamera3d.html#class-xrcamera3d) to enable vision, and two
 [`XRController3D`](https://docs.godotengine.org/en/stable/classes/class_xrcontroller3d.html#class-xrcontroller3d) (one for each hand) to add the controllers.
 
+> REMEMBER: use `XRServer::find_interface`. disable vsync at runtime using `DisplayServer::window_set_vsync_mode()`. And set `Viewport::use_xr`.
+
 ## Further Reading
 
 * [[https://docs.godotengine.org/en/stable/tutorials/xr/setting_up_xr.html#doc-setting-up-xr]]