HTC Aria Quick Start Manual page 8

About the Home screen (continued)
Navigating the Home screens
On any Home screen, slide your finger
horizontally across the screen to go to the left
or right home screen.
You can also swipe your finger left or right
over the optical trackball to move to the next
or previous screen.

For quicker access to a Home screen, press
Home while on the main Home screen to while on the main Home screen to
display a snapshot of all the Home screens, and
then tap a screen snapshot to go directly to
that screen.
Tip: On any Home screen, you can "pinch"
the screen with two fingers to display a
snapshot of all the Home screens.