There is an Applicants menu on the left hand side:
Click into here. There is a standard view of My Active Applicants.
This will show a list of all the Applicants that applied to your adverts sent via Mercury, that are against any active Vacancies that you are working on.
From here, you can use the filters to view all Candidates linked to a particular role or Client or by any other filters required.
TIP: All Applicants will also be listed against the Vacancy they have applied for. Click into the Applicants tab on the Vacancy to view them.
One more tip...all roles that a candidate has applied for will also be listed on their record, under the As a Candidate tab:
