The three tutorials you linked seem pretty good at explaining exactly what your question is about, what part of them confuses you?
[quote:3jv2vsej]how big the safe zone is :
The safe zone is exactly your original project size (While scaling outer your whole project will be scaled to fit inside the available space)
[quote:3jv2vsej]what window size and layout size to have :
Your choice completely..
[quote:3jv2vsej]how to center the screen:
scaling will automatically center to the original center of your project view if your layout is set to unbounded scrolling (which is the middle of the dotted rectangle), if you want to scrollto somewhere else use either the scrollto behaviour or the system scrollto action
[quote:3jv2vsej] how to scale the sprites(if they need scaling, and what size should they originally be created in):
The fullscreen option will scale yor sprites for you.. You'd probably want to create them the biggest size they will be shown, for bigger is unnescessary to make them look good..
[quote:3jv2vsej]what if I want to have different "pages" on one layout like in this example:
Like you said, you have an example already, it uses scale outer as far as I can see..