Hi,
Interacting with a singleton is exactly the same, the only and great advantage is that you don't have to worry about it being duplicated, so you can have for each of your individual level scenes, managers of all sorts and you can run an individual level without having to start from the beginning of your game, via the menu and all. and when playing from the start, all managers within each level you'll load will be removed to only ever keep the first and only one instance generated.
that's all, accessing a singleton is then exactly the same, it will received event being broadcasted for example.
Bye,
Jean