1. Go to Candidates -> Job applications, followed by selecting your desired job from the selection box in the bottom left.
2. Once that's done, have a look at the matching report, as well as the applicant's experience and education.
You can always choose to email candidates directly or message them on WorkValues (they'll also get an email notification).
If you believe they should move on in the hiring process, click the Accept button and add a message to them. Once you accept the applicant, an email thread will be created between you and them, informing them that they can continue the conversation with you over there.
On the other hand, if you believe that the applicant should not go forward in the hiring process, click the Reject button and choose an appropriate message.