Please make sure you have the correct information in your profile, first. You can update your profile by hovering over the gear icon in the top right and clicking profile settings.
Once you open your profile you will need to make sure you have your mobile number listed as it will need to receive SMS messages from us.
After you update the correct info for your email and phone, you can then enable two factor using the dropdown toggle in your profile (pictured above). Click save after you finish and you're done.