The loading spinner is a useful prefab for when you need to indicate that data is loading or a task is being peformed and you want to prevent accidental input from the user while they are waiting.
It's very easy to use, simply drag the Loading Spinner component to your node editor and connect a signal to Show when you want to display it and Hide when you are done and want it hidden.
Above you can see a typical use case in combination with the Query Records node, trigger the Show signal when you start the request to the cloud services and then Hide when it finishes (remember to capture both successful and failed requests).
A feature of the loading spinner is that you can do multiple consecutive Show signals and it will keep track of the count and then require the same amount of Hide signals to close. This is useful if you have parallel request to the backend and you want to make sure all requests have completed before you hide the spinner.