Screen Saver is difficult to find because it isn't that commonly used. I have used one in years. The real way to "save" a screen is to have it go off. Jiggle the mouse or hit a key and it is back. A screen saver doesn't really save your screen. It just gives you something nice to look at when you aren't using the computer.
WIth my computer it is showing the other accounts in the lower left when the last logged in account is in the center. Typically in Windows 8 there was an arrow to go backwards to choose a different account based on what you described. Either way it should have some way to switch to the other accounts easily.