Only use 2FA on devices you trust. It's not recommended to setup 2FA on a shared or compromised device.
To setup 2FA in the billing area, head over to the billing area and login
Next, head over to Security Settings which you can find here:
You can then follow the instruction on the screen. You will need to download Google Authenticator or DUO from the android or IOS app store.
To setup 2FA in the game panel area, head over to Account Security in the game panel area.
Hit Enable 2-Factor Authentication to show a QR code that you can scan.
For this, download an app on your phone that is a 2FA app, such as Authy.
Then, add a new account and scan the QR code. Once it is scanned, type the token that you have on the app into the Authentication Token box.
You are set and fully protected! Rememeber to keep the device near you when you login so can authenticate yourself!