The best way to preview what an applicant will see is to log in as applicant:
APPLICANT USER ROLE
As an administrator, you can login as an existing applicant via users in the navigation list.
If you do not wish to log in as an existing applicant, you can create a text applicant with your personal email or test email address.
If you try to preview the form, or are set up as both an Administrator and an Applicant your Administrator access outweighs the applicant role, and you will still see internal & administrator only questions.