Thanks Ichkeria...I managed to work it out after all. Changing the P/W in my Samsung Tablet was even harder.........why can't they just have a big button that says "Change Password" instead of hiding the facility in a sub-sub-sub menu somewhere !
The Samsung world is a black hole to me but I think the reason it's like that on these devices is simply for convenience of coding and possibly space. It takes a lot of the grind out of writing and maintaining apps if you have the external parameters configurable from a central app elsewhere. I agree it's not very intuitive if you are used to desktops : I keep forgetting I can turn off the wretched notifications for various things. They seem to keep wanting to turn themselves back on in a lot of cases by default