Multi-controller and R5

Sorry if this is a basic question but I have just received my R5 and have not used a camera before with multi-controller. I would like to use the multi-controller to move focus point or to indicate where to track. I know that the touch screen can be used but would prefer to use the multi-controller. When I first select the focus mode I can use the controller to select the point but once selected I cannot subsequently move it. Any ideas? I cannot see how to customise it.

Thanks