While viewing your Inbox, swipe the screen up and down to scroll through the list of messages. The following icons are available at the top right of the Gmail Inbox:
Compose : Tap to start a new Gmail message.
Search : Tap to search within the Gmail application.
In addition, while viewing your Inbox you can:
Swipe a Gmail message off the screen to the left or right to quickly and easily archive the message. Tap Undo to restore it to your Inbox.
Tap the letter icon (or contact photo) to the left of one or more messages, then tap the Delete icon to delete it/them.
While viewing a message, swipe the screen left and right to scroll through all of your messages and use the following icons:
Archive : Tap to send the message to your archive folder.
Delete : Tap to delete the message.
Unread : Tap to return the message to an unread state.
If you are viewing a message or another label, tap the Back Key (in the Front Touch Keys bar) until you return to your Inbox.