Most of the time when you want to check your Gmail you would use the default browser or the opera. Have you ever noticed that there is a link when you open up the Gmail page? This link is Get faster Gmail. When you click this link it will install the Gmail application with which you can access your Gmail faster than ever before.
This installation is a normal installation as you do it for other applications. When you are done with the installation, go to applications and select the Gmail icon as shown below.
When you enter the username and password the application opens up and you can see your mail box as shown below. There is navigation in the application where you can move up and down, centre click is for opening the selected mail. Also it has options like Refresh, Search Mail, Compose Mail and Exit Gmail.