Multi factor authentication is a good way of keeping your account safe and secure as you will only be granted access to your account if you can successfully present two pieces of evidence to an authentication:
Username & Password
For this, you need the Google Authenticator application which can be downloaded here
In the profile settings, you can select the tab Two Factor Authentication.
Then, as shown below you can switch the tab on to activate the next step
When you select this tab, a pop up will appear like this with a scannable QR code:
From your Google Authenticator application, you can scan this QR code and will receive a 6 digit code.
When you type the code here and click confirm, the steps are complete.
You can check that it worked by logging out. When you attempt to log back in you will see a screen like so:
The code on Google Authenticator refreshes every 30 seconds to ensure extra safety on the account.
Now, each time you attempt to log in, you can type the code from the application for an extra security measure.