To enable 2FA You first need to go to your account settings.
Once in your account settings click the Enable 2FA button
Once you are there you should see a QR code, a token and 2 text fields.The first one is where you will put the numbers from Authy and the second is where you fill in your password to verify that it is you.
When you are inside the Authy app (or 2FA app of your choice) add an account and scan the barcode like so.
That's it! Simple as can be. Just fill in the fields with the code from the app and your password and you should be good to go.