There are two ways to invite applicants to an open call on Harri.
First, you can screen your applicants and invite those qualified candidates by moving them to the Interview column. Select the time, date and location of the open call, then save. This will send an interview invitation to the candidates, who will confirm their interview time.
The second way is by creating an open call within a job posting. Edit a job posting, then scroll down to Create New Open Call and fill in the time/date/location. You may have to fill in the location if it's not taking place at the property whose job you're in. Save, then you can attach that existing open call to subsequent job postings for that property.