This is what I mean about the five screens. As a frame of reference, I'll call them 1, 2, 3, 4, 5.
When I start the phone, it is on screen #3. I can swipe left or right one screen at a time. Going left gets me to screen 2 and then if I continue, to screen 1. Swiping right gets me to 4 and 5. All screens have a dot in the lower right and lower left that do the same as swiping that direction if tapped, and also have an icon in the lower center that opens the "everything" screen.
If you download an app, by default, it goes to the "everything" screen. You can then add it wherever you like by swiping to that screen, opening the "everything" screen, and long-tapping on the app, then placing it as desired. You can drag apps between screens. If you want to remove it from a screen, you can drag it to the button that opens the "everything" screen, and it'll switch to a trashcan that removes the alias from that screen when you release.
Here's what I have where:
Screen 1 - this is the fun/goofing around screen: moon phase widget, Trailmaps Pro, Tricorder (toy), Terminal Emulator, Google Voice, Aldiko e-book reader, Parallel Kingdoms (game), Dice, gStrings (guitar tuner)
Screen 2 - news feed widget, calendar widget, Camera, Gallery
Screen 3 (startup home) - Messaging, Facebook, YouTube, app Market, Phone, Contacts, Browser, Maps
Screen 4 (utilities) - at top is a widget letting me turn on/off wifi, bluetooth, satellite, sync and brightness with one tap - below that: Google Sky, Fandango, Barcode Scanner, Phones, Compass, a notepad app, Unit Converter, Calculator, Car Home (you can tap Search and say "map of gas stations" to see all nearby gas stations or single-tap for navigation or maps), Gmail, Here I Am, Uninstaller
Screen 5 - social media - Facebook widget up top that lets you update status and see your news feed. Below that, Google Search bar. Below that; Gigbox, My Account (T-Mobile), Google Talk, eBuddy
All apps and widgets can be moved or removed, and the labels I gave some screens are only what I'm calling them, the OS doesn't care what you put where.
I have some cleaning up to do, remember I've only had the phone a little over a week. But that's an idea of how at least one person has it set up.