To add candidates to a new role, go to the Hiring section of the app. Find the role you're hiring for, and click 'Invite candidates'. If you're adding the first candidate for the role, you'll have to make a role first (see how here).
Candidates are invited using their email addresses. An email will be sent to the candidate, prompting them to sign up and complete the data collection survey. When they have finished the survey, admins of the company will be notified by email. Admins can find links to the candidate's analysis in either the Hiring section, in the role they were added to, or in the Teams section, in any team they were added to.
Candidates are not included in the original team analysis, so won't affect your employee team reports.