The Inbox: Email messages you’ve received will be displayed as a list here. Click an email in the list to open it.
The Left Pane: This pane contains quick links to your inbox, sent items, drafts, and the All Mail view. Below those links, you'll see links to the automatic mail categories, and any labels you've created..
The Compose Button: Clicking this will start composing a new email message.
The Search Field: Click here to search through all of your email.
The Tool Bar: The toolbar above the inbox contains commands to interact with your inbox and email. The available commands will change based on what you have selected..
Right Side Panel: This panel displays buttons for some other Google services that you can use with your Gmail, including Calendar.