To manually import a candidate into one of your Job's Hiring Processes, start on your homepage and click the Job you wish to add them to.
Once inside the Job's page, click the Job actions button in the upper-right corner.
Select "Add Candidate".
This window will appear. Fill in your candidate's name and contact information and click Add candidate. You will also have the option here to decide whether or not you'd like to notify your organisation about their insertion.
Once you click Add candidate, the candidate will immediately appear in your Job's "Applied" Stage.