Reading Your Messages
From your Gmail inbox, tap a conversation that contains the message you want to read.
The conversation opens to the first new (unread) message, or to the first starred message, if you’ve previously starred a message in the conversation.
Tap to set labels for the message to help organize your messages.
Tap the Contact's picture to open Quick Contact.
Gmail Inbox Header
Gmail Message Header
While viewing a message, you can tap the message action icons on the Gmail inbox header, the message header, or at the bottom of the screen.
Gmail inbox header icons
The Gmail inbox
header icons include the Back icon 
(returns to the Gmail inbox),
the Archive icon 
, the Delete icon 
, the Mark read/unread icon 
, and the Menu icon 
.
Gmail message header options
Tap the Contact’s picture to open the Quick Contact options.
Tap the Reply icon
to reply to the sender.Tap the Menu icon
to reply to all, forward the
message, star the message, or print the message.
Message action icons
Tap an action icon (at the bottom of the message) to reply, reply to all, or forward the message.