Go to Volunteers > Report and select the event you’d like to add the volunteer into from the drop-down at the top of this page. Click the "Expand All" button, or select the job and shift to expand them individually. You’ll notice an option in the lower right-hand corner of every expanded shift that says, Add a volunteer to this shift.
When you click this, a blank volunteer profile will appear. Add as much or as little information as you’d like about the volunteer you’re adding. Remember: even “required” fields are optional when you’re adding a volunteer as an administrator.